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.
Firefox on iOS still doesn’t support extensions and yes, is still based on the same engine as the other browsers.
YT ads are not blocked on Firefox on iOS, I just tried.
oh yeah, I forgot about the whole apple engine. it’s kind of nonsense that all browsers have to use it. Let’s hope this will change when Apple introduces sideloading