I use Linux and try to use Teams in Chrome for some client communications. It's been a frustrating experience to get myself logged in. There's a lot of confusion about my live account, microsoft account and several others that i'm not familiar with. I usually just run it without logging in now and just type my name.

Slack is definitely better but I have had issues with message delivery and things especially across the "native" desktop application and the mobile app.

Flaky Wifi connection? Maybe Slack just retries more, and Teams gives up easily?