Microsoft has no intention of solving this issue. It is intentional and is designed to irritate you into switching away from POP or IMAP to exchange servers your email accounts with them. Here is their statement again"
Microsoft sent this out in an email:
"The safety and security of your information is top priority for Microsoft. To help keep your account secure, Microsoft will no longer support the use of third-party email and calendar apps which ask you to sign in with only your Microsoft Account username and password. To keep you safe you will need to use a mail or calendar app which supports Microsoft’s modern authentication methods. If you do not act, your third-party email apps will no longer be able to access your Outlook.com, Hotmail or Live.com email address on September 16th"
So, the proper answer is that Microsoft is irritating you intentionally to make you go ahead and switch your email account from POP3 or IMAP to a Microsoft Exchange account before September 16, 2024. Delete your existing account in Outlook 365 and then add it back allowing Outlook to do it automatically. It will set up an exchange server type account.
I did this and have had no more issues. A couple of things I had to do were switch my calendar back to my preferred email account which wasn't the hotmail account and create a rule in the new exchange account that instructs it to deliver incoming messages to my preferred email account inbox. I like to have messages delivered from my total of six email accounts to one inbox.