We’ve been using Microsoft Teams as well as the entire office suite, and we’ve been positively surprised. There is an occasional clunky UI you come across, but the feature set is far superior to Slack or Zoom, and the ecosystem integration is nice.
Frankly most of these tools have been at feature parity since before Covid.
At the end of the day, just about every team that I worked with had a WhatsApp group that they actually used to chat in. Having a bad product as your internal chat is how you get shadow IT like WhatsApp where people are discussing your proprietary information on a third party service.