Latest NewPipe 0.27.2 installed from F-Droid is able to play videos for me. But you might also try PipePipe or Tubular, which I mostly use these days.
I’m using LibreWolf with uBlock Origin, Privacy Badger and NoScript where I selectively allow scripts and I never got an ad served on YT
Can’t stop laughing staring at the UKIP logo on that thing