Out of the box it can play audio in the background, and now that extensions are available you can block ads as well. You don’t really need constantly updating 3rd party clients or questionable firewalls anymore if you just want usable youtube on a phone.
Sorry, you already tried what I would do too. I will ask in the original post (this is a x-post) and tag you.
Here the link for you: https://lemmy.world/comment/5576470