Actually there’s some support for Wayland. Tried it last year, but had to do serious rummage trying to make it work. For starters I can recall it spitted a video but the command throwed an error at the end and could not understand why. Also i seem to recall the video stopped way after finishing the command.
Even had to recompile all of ffmeg to add support for wayland recording (though Gentoo makes this really easy). One thing for certain is that Gentoo’s ffmpeg stable version is fairly behind from upstream’s so that could have had a hand on it too.
I wish in countries like mine things like electric toothbruses weren’t like luxury items but things everyone could have. Got mine too late for my teeh but ever since I got it I no longer worry about dental plaque. Cavities and such things are hell on earth. Or, well, in your mouth.