Aside from the surge...
...I had to use this Teams™ thingie for work.
You can't open side by side the chat panel and the files folder panel to load and unload files, so one person can guide you through whatever you need doing. Since the dawn of windows, the usability of having WINDOWS, is to have TWO of them doing different things. Open new view? Nope. New task? Nope.
No button, tool, right-click menu, nothing IN YOUR FACE to allow viewing the chat in one tab, and the uploaded files in another, with simultaneous view. Not just that, it FORGETS the folder you were in, going back to the root of the folder structure, or where you last logged in.
We are talking about having 3 different things in the screen: a chat windows, a cloud window, and a local file explorer window. The program doesn't allow the 2 first to happen at the same time, which is ABSURDLY STUPID. You can't edit files on the source either: you must download stuff into a temp folder, edit the stuff, and then re-upload, UNLESS you have OneDrive working on your machine, and then you edit YOUR file, which gets uploaded.
You can't get 2 copies of Teams on the same machine either.
IT icon, because the punks that built it never did IT or User Interface in their lives.