Kudos for at least trying to address this, MS should hang their head in shame, this is not the hardest problem to solve these days. If we could do it in 1995 they should be able to do it 30 years later.
Office 365 actually works better in Firefox in Linux than any other browser in Windows. It's like they've kind of given up on the whole OS thing, and have just decided to go with Linux.
Granted I haven't tried O365 in about a year since it was so unusable in Firefox.
As far as teams goes, I use it in the same version chromium on the same OS on two different computers; one works fine most of the time (main issue is it sometimes switches the audio back to the first item listed by Linux, which is not my USB headset). The other computer is terrible. Somewhere between 4-48 hours it pops up a tiny (maybe 40px) banner at the top saying "you need to sign in again" meanwhile there are no notifications and any messages I send are silently queued with no obvious indication that they haven't been delivered. Before I figured this out, I was just randomly out of communication with my coworkers, with both sides thinking we were sending the other person messages that they were ignoring. Clicking the "sign in" button on the banner just seems to reload teams and doesn't even ask me to sign in.