That is absolutely not "the main problem" with Teams. It's UI is not very well thought out at all and notifications work with the reliability of a rooster on ketamine.
The only three value propositions Teams has over Discord are:
* Support for threads - albeit again very inelegantly.
* The ability to embed web apps as tabs in a Teams page - this is my favourite feature
There's other minor problems like insane chat latency, but I can work with that. Voice and Video generally works fine.