YouTube throttles some of the more popular instances. Find a less popular one. I was also finding that thumbnails and subtitles weren’t loading on some instances. After switching to a fairly obscure one, everything works. You could also try piped which I find generally works better and I like the interface better.

It really depends whether he got the devs of “Lutris, Heroic, Legendary, Bottles, etc.” to agree to use the unified runtime before starting this project. As long as he gets most of the big players to join then it will actually become the only standard worth using.