Sharing single displays or specific windows on Wayland is easy - Chrome and Firefox, or app like OBS can do it; if your conference app cannot do it, ask the vendor why.

Here's an anecdote: sharing a single X11 display on my two-display setup works just fine with Microsoft Teams, I use it almost daily.

That Linux MS Teams client can only do read-only sharing (no giving control to remote party) is another matter, which bothers me a lot.