2. "The right fucking" Gnome-exclusive API is, obviously, Gnome-exclusive, and just didn't work for me for the reasons I mentioned in my original message, and probably didn't for them either (my guess because they have a custom H264 encoder for latency/licensing reasons). The "less-Gnome-specific" XDG portal API, Pipewire-based, wasn't really usable when the distro is not even packaging Pipewire.
My go-to conferencing solution is still Jitsi Meet and I am well aware of how crazy the entire situation is, even for browsers.