Every once in a blue moon you get logged out and need to log in again. Teams seem to cache some stuff and not others so in that case behavior isn't exactly intuitive.

I am not the least surprised that it trigger crashes.

On Mobile, I do it with a browser "Show Desktop Version" and click on the "Continue on this browser" option. This is only an option when one doesn't need to fully participate in Teams, which is the case for me.

I do not currently use a Microsoft account for anything. I have one, and once in a while, I log in with it for some reason or other.

Everything else is a Office 365 account tied to an email provided by the people funding that access.

For me personally, using OSS gets the job done for all my computing needs otherwise.

Not last time I tried. That flow (i.e. you are not part of/logged into an institutional Teams account) is completely broken. Teams makes you go create a free Microsoft account, which then doesn't work to log into Teams.