I have the same problem on my Machine. I already uninstalled teams completely and removed all folders with Teams related data from my Machine. That's why I think that the problem is not coming from teams directly, but from another component on the computer that teams uses!?!?
Or am I on the wrong track here?
Not sure if it helps, but since I have this Problem the following software pieces were update:

and I have received the following Updates:

maybe there is a Teams engineer login at this. Here is the List of exception I have found in the Teams log:
warning -- File not found for desktop-config.json. Ignore if this is the first-run of the app. Initializing a new default config.
Line 199: Mon Sep 20 2021 09:18:52 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- isSettingValid: preauth settings creation is not present
Line 211: Mon Sep 20 2021 09:18:52 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- Error occurred while saving env_config.json
Line 311: Mon Sep 20 2021 09:18:53 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- spellCheckerService dictionary download failure languageCode=en-US
Line 385: Mon Sep 20 2021 09:18:53 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- Can not get WebAccountId for active signed in user
Line 486: Mon Sep 20 2021 09:18:54 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- Error occurred while saving env_config.json
Line 622: Mon Sep 20 2021 09:18:57 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 623: Mon Sep 20 2021 09:18:57 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 894: Mon Sep 20 2021 09:19:05 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 1384: Mon Sep 20 2021 09:53:39 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 1521: Mon Sep 20 2021 09:53:43 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 1522: Mon Sep 20 2021 09:53:43 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 1529: Mon Sep 20 2021 09:53:43 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 1579: Mon Sep 20 2021 09:53:44 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- Error saving cookie
Line 1631: Mon Sep 20 2021 09:53:46 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- RegistryService: Unable to read registry value: Message: Unable to read RegKey
Line 1632: Mon Sep 20 2021 09:53:46 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- RegistryService: Unable to read registry value: Message: Unable to read RegKey
Line 1634: Mon Sep 20 2021 09:53:46 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- RegistryService: Unable to read registry value: Message: Unable to read RegKey
Line 1635: Mon Sep 20 2021 09:53:46 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- RegistryService: Unable to read registry value: Message: Unable to read RegKey
Line 2235: Mon Sep 20 2021 10:27:13 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 2383: Mon Sep 20 2021 10:27:16 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- Error saving cookie
Line 2390: Mon Sep 20 2021 10:27:16 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 2391: Mon Sep 20 2021 10:27:16 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 2397: Mon Sep 20 2021 10:27:16 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 2586: Mon Sep 20 2021 10:33:27 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- setIcon error: Message: Cannot read property 'setImage' of null
Line 2614: Mon Sep 20 2021 10:33:28 GMT+0200 (Mitteleuropäische Sommerzeit) <7476> -- error -- [screenSharing][control] appSharingToolbar: "this" does not bind to AppSharingToolbar object in closeWindow
Line 2811: Mon Sep 20 2021 10:34:14 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- [DesktopConfig] Get SignedInActiveUser Undefined value: UserAccounts existed: true, accountType existed: false
Line 2812: Mon Sep 20 2021 10:34:14 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- Can not get UserProfile for active signed in user
Line 2961: Mon Sep 20 2021 10:34:14 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- Error occurred while saving env_config.json
Line 3154: Mon Sep 20 2021 10:34:14 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- spellCheckerService dictionary download failure languageCode=en-US
Line 3239: Mon Sep 20 2021 10:34:15 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- Error saving cookie
Line 3254: Mon Sep 20 2021 10:34:15 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 3255: Mon Sep 20 2021 10:34:15 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 3521: Mon Sep 20 2021 10:34:19 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 4399: Mon Sep 20 2021 11:01:07 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 4540: Mon Sep 20 2021 11:01:09 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- Error saving cookie
Line 4547: Mon Sep 20 2021 11:01:09 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 4548: Mon Sep 20 2021 11:01:09 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 4554: Mon Sep 20 2021 11:01:09 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 4869: Mon Sep 20 2021 11:09:15 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 5019: Mon Sep 20 2021 11:09:18 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- Error saving cookie
Line 5026: Mon Sep 20 2021 11:09:18 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 5027: Mon Sep 20 2021 11:09:18 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 5033: Mon Sep 20 2021 11:09:18 GMT+0200 (Mitteleuropäische Sommerzeit) <11644> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 5525: Mon Sep 20 2021 11:15:00 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- [DesktopConfig] Get SignedInActiveUser Undefined value: UserAccounts existed: true, accountType existed: false
Line 5526: Mon Sep 20 2021 11:15:00 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- Can not get UserProfile for active signed in user
Line 5675: Mon Sep 20 2021 11:15:00 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- Error occurred while saving env_config.json
Line 5888: Mon Sep 20 2021 11:15:00 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- spellCheckerService dictionary download failure languageCode=en-US
Line 5964: Mon Sep 20 2021 11:15:01 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- Error saving cookie
Line 5979: Mon Sep 20 2021 11:15:01 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 5980: Mon Sep 20 2021 11:15:01 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 6217: Mon Sep 20 2021 11:15:05 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 7752: Mon Sep 20 2021 13:14:57 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 7902: Mon Sep 20 2021 13:15:00 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- Error saving cookie
Line 7909: Mon Sep 20 2021 13:15:00 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 7910: Mon Sep 20 2021 13:15:00 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 7917: Mon Sep 20 2021 13:15:00 GMT+0200 (Mitteleuropäische Sommerzeit) <4652> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 8677: Mon Sep 20 2021 13:36:03 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- [DesktopConfig] Get SignedInActiveUser Undefined value: UserAccounts existed: true, accountType existed: false
Line 8678: Mon Sep 20 2021 13:36:03 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- Can not get UserProfile for active signed in user
Line 8828: Mon Sep 20 2021 13:36:04 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- Error occurred while saving env_config.json
Line 9040: Mon Sep 20 2021 13:36:06 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- spellCheckerService dictionary download failure languageCode=en-US
Line 9112: Mon Sep 20 2021 13:36:07 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- Error saving cookie
Line 9127: Mon Sep 20 2021 13:36:07 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 9128: Mon Sep 20 2021 13:36:07 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 9359: Mon Sep 20 2021 13:36:10 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 9670: Mon Sep 20 2021 14:56:43 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 9832: Mon Sep 20 2021 14:56:46 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- Error saving cookie
Line 9844: Mon Sep 20 2021 14:56:46 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 9845: Mon Sep 20 2021 14:56:46 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 9851: Mon Sep 20 2021 14:56:46 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 10380: Mon Sep 20 2021 15:27:15 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- Error saving cookie
Line 10388: Mon Sep 20 2021 15:27:15 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 10389: Mon Sep 20 2021 15:27:15 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 10396: Mon Sep 20 2021 15:27:15 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 11049: Mon Sep 20 2021 16:17:43 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 11193: Mon Sep 20 2021 16:17:46 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- Error saving cookie
Line 11200: Mon Sep 20 2021 16:17:46 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 11201: Mon Sep 20 2021 16:17:46 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 11207: Mon Sep 20 2021 16:17:46 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 11507: Mon Sep 20 2021 16:21:12 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 11657: Mon Sep 20 2021 16:21:14 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- Error saving cookie
Line 11669: Mon Sep 20 2021 16:21:14 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 11670: Mon Sep 20 2021 16:21:14 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 11677: Mon Sep 20 2021 16:21:14 GMT+0200 (Mitteleuropäische Sommerzeit) <18848> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 12266: Mon Sep 20 2021 16:21:50 GMT+0200 (Mitteleuropäische Sommerzeit) <22784> -- error -- [DesktopConfig] Get SignedInActiveUser Undefined value: UserAccounts existed: true, accountType existed: false
Line 12267: Mon Sep 20 2021 16:21:50 GMT+0200 (Mitteleuropäische Sommerzeit) <22784> -- error -- Can not get UserProfile for active signed in user
Line 12416: Mon Sep 20 2021 16:21:50 GMT+0200 (Mitteleuropäische Sommerzeit) <22784> -- error -- Error occurred while saving env_config.json
Line 12512: Mon Sep 20 2021 16:21:50 GMT+0200 (Mitteleuropäische Sommerzeit) <22784> -- error -- spellCheckerService dictionary download failure languageCode=en-US
Line 12705: Mon Sep 20 2021 16:21:51 GMT+0200 (Mitteleuropäische Sommerzeit) <22784> -- error -- Error saving cookie
Line 12720: Mon Sep 20 2021 16:21:51 GMT+0200 (Mitteleuropäische Sommerzeit) <22784> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 12721: Mon Sep 20 2021 16:21:51 GMT+0200 (Mitteleuropäische Sommerzeit) <22784> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 12960: Mon Sep 20 2021 16:21:55 GMT+0200 (Mitteleuropäische Sommerzeit) <22784> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Line 13651: Mon Sep 20 2021 16:42:18 GMT+0200 (Mitteleuropäische Sommerzeit) <6856> -- error -- [DesktopConfig] Get SignedInActiveUser Undefined value: UserAccounts existed: true, accountType existed: false
Line 13652: Mon Sep 20 2021 16:42:18 GMT+0200 (Mitteleuropäische Sommerzeit) <6856> -- error -- Can not get UserProfile for active signed in user
Line 13801: Mon Sep 20 2021 16:42:18 GMT+0200 (Mitteleuropäische Sommerzeit) <6856> -- error -- Error occurred while saving env_config.json
Line 14018: Mon Sep 20 2021 16:42:19 GMT+0200 (Mitteleuropäische Sommerzeit) <6856> -- error -- spellCheckerService dictionary download failure languageCode=en-US
Line 14090: Mon Sep 20 2021 16:42:19 GMT+0200 (Mitteleuropäische Sommerzeit) <6856> -- error -- Error saving cookie
Line 14105: Mon Sep 20 2021 16:42:19 GMT+0200 (Mitteleuropäische Sommerzeit) <6856> -- error -- VideoBackgroundsDownloader: failed with error: failed to get image thumbnails as path C:\Users[MyName]\AppData\Roaming\Microsoft\Teams\Backgrounds\Uploads does not exist and reason LOCAL_IMAGES_FAILED_TO_FETCH
Line 14106: Mon Sep 20 2021 16:42:19 GMT+0200 (Mitteleuropäische Sommerzeit) <6856> -- error -- VideoBackgroundDownloader: failed to fetch user uploaded images without thumbnails with undefined
Line 14344: Mon Sep 20 2021 16:42:23 GMT+0200 (Mitteleuropäische Sommerzeit) <6856> -- error -- BluetoothLE::ScanStop -- Scan already stopped, no watchers present.
Regards Michael