If you just need the chats, its actually lighter and faster in MS Edge than in the app Ive found. They are using some newer Edge shit in the web thats not yet ported to the app.
I don't use Windows all that often, and I've found that Outlook is much less annoying in a browser (even Firefox!) than the app. It feels less laggy.
https://docs.microsoft.com/en-us/microsoftteams/get-clients?...
Yes, I too find that all Office apps is faster on the Web.