I can report that Wayland + Chromium screenshare does work. I haven't tried screenshare with Wayland + Firefox, mainly because I think I had other video/audio problems during calls with Firefox.

This is on Gnome (Ubuntu) so there may be some default Ubuntu config that makes Wayland screensharing work, may need to do some searching online if your distro/setup doesn't have Wayland screensharing working.