I'd also suggest maybe adding the channel names (like the comment you posted here) to the app itself (although i think it's cool when it's unnamed and you get the old-school feeling of channels just being numbers).
Also, I'd love to have permalinks for the channels. Not for the individual videos themselves, but just a link that when sharing would bring somebody else to the same channel you're watching right now.
Another thing, although probably outside your control, is that I use a Firefox extension called "SoundFixer" that I use to force the youtube audio to mono (since a lot of channels are annoying to me using headphones, they pan the audio sources too hard left/right and it's super distracting), but it doesn't seem to work on this website, probably because of the way they're embedded. I don't know if this can be changed somehow, or have a mode to force mono audio (which would be also oldschool like old TVs with one speaker only!). It's probably too niche and hard to do though.
Also I don't seem to find any volume control except mute?
In windows you can also go to "Ease of access audio settings" and click "Turn on mono audio". Useful for games which have positional audio which gets annoying (sf6 training room for example).