Is there a single high level engineer (like, whatever L9 is at Google where you make millions of dollars for being a savant) working on Teams? If not, why not? A ton of its problems seem fixable. Discord/WhatsApp and Teams are both Electron apps from what I can tell. Discord/WhatsApp very usable, so it's not like Teams is doomed from the get go without a full rewrite.

Is the entire thing written by a team who don't care/don't know any better/can't do any better?