Managing sound and video settings during Teams meetings and calls
I was able to fix this on my Pixel 5 today by clearing both the Cache and User data for the Teams app, which is similar to installing for the first time. Notice I say first time. For those who uninstalled and reinstalled the Teams app and it did not fix their problem, it may be because those two items were not cleared before you uninstalled. Many times apps leave stuff behind when they are uninstalled and then reuse that same data when they are reinstalled, So if the problem is in that data, it is just carried forward. I'm not saying this method will definitely solve the problem on your phone, but give it a try.
I have not read every post in this thread, so bear with me if this has been said already, but another possibility is enabling permission in Teams for Nearby devices. I have not experimented with this yet to see if that is required, but I did enable that when I was troubleshooting.
Good luck. I feel your frustration.