Teams is ok, it's just too much functionality. I have problem finding the correct chat room for the voice call right away, I always have to double check if I am in the correct chat.
My problem with Teams really boils down to the absolutely terrible desktop user interface. It's fiddly, hard to work with, and hard to figure out how to do a lot of things. You can't make the window smaller than a certain (way too large) size, and you can't have more than one window. It's just painful, intrusive, and unpleasant.