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.
Excuse me, did you even read what you have linked? The first link literally explains the privacy policy of “the NewPipe’s” website.
Also, what the fuck is even newpipe.app? https://github.com/TeamNewPipe/NewPipe The GH repo as well as the F-Droid release all link to newpipe.net and I couldn’t find any reference to the .app website there.