However, applications that just grabbed X11 framebuffer won't work. They have to use respective APIs with user control ("portals") for that. Some do (Chrome, Firefox), some don't (MS Teams).
If you're forced to use an application that only supports the X API, you can kludge it to work by VNCing to yourself with x11vnc and then screencasting the x11vnc window.
I use it every day. I can share screen in Google Meet, Zoom, Slack Huddle, and many others. It doesn't work in Signal, though, because Signal is using an outdated version of Electron.
Since each company sort of sticks with 1 tool for every employee, could be kind of a deal breaker if they pick a tool that can't screen share on Wayland.
A friend of mine couldn't share his screen on meet or teams and I had to change it from Wayland to X11 to make it work. His was a Ubuntu 22.04 distro (GNOME) 4 month old install. Wonder why that happened.
No! The Wayland protocol provides no mechanisms for screen sharing and it is not intended that it ever will. Screen sharing has to be done by external protocols that are either compositor specific or using a somewhat standardized dbus protocol that is completely separate from Wayland.
It seems to work for a lot of people, but I still get constant crashes using xdg-desktop-portal-wlr, despite trying multiple GPUs, extensive testing etc. I will probably dive into the code when I get some time.
However, applications that just grabbed X11 framebuffer won't work. They have to use respective APIs with user control ("portals") for that. Some do (Chrome, Firefox), some don't (MS Teams).