As a victim of this bundling (RIP internal XMPP w/ OTR), I'm happy someone is looking into this.
As a recovering Teams user, I'm sure it's continued to marginally improve over the years, but I was impressed, when I was forced to use it, at how generally bad it was at almost everything it needed to do, including just basic chat. My fondest memory is of how impossible it was to scroll up in the chat more than a few messages before all messages needed to be fetched from the server again. It made navigating around large conversations impossible as you'd scroll back a bit, wait for it to load, reference the messages you need, then scroll back to the most recent stuff and, again, wait for it all the load. You'd wait for everything to load even if there were no new messages sent between the times you viewed things.
