I used the default Mail Microsoft Store app for the past 2 years at work. The past 6 months, it's been telling me to move to Outlook desktop app. A couple weeks ago, it wouldn't allow me to use the Microsoft Store app anymore, so I installed the desktop version, tried to login, and got an error message that my account would only work on the webapp.

Set up Thunderbird on my work desktop that day, and haven't looked back. Wish I would have way sooner, to be honest.