Screen sharing is one of those topics that were addressed in the last few years in wayland, I personally shared my screen through BBB on Firefox successfully multiple times. Admittedly, not all features (like sharing of individual windos or browsertabs) were available (don’t know, if that’s fixe now). Can’t speak for Zoom, but I don’t see how it should differ in the browser to something like BBB. As for their proprietary application, the interfaces to capture screen content are there; if they don’t want to use it and therefore enable wayland users to use their system, that’s on them. Same goes for nVidia: it took them way too long to accept that wayland is a thing and start supporting it in their video drivers.