Also don’t forget UntrackMe and UntrackMe Lite. It converts YouTube, Twitter, Instagram, and Google Maps links to respective Invidious, Nitter, Bibliogram, and OpenStreetMap alternatives in your browsers. Works really well.
As far as alternatives to the YouTube app, but not the service, there are others besides NewPipe such as SkyTube/SkyTube Extra, YaShlang, and HoloPlay (uses Invidious) among others.
Also, NewPipe is a multi-service app. It also does SoundCloud, MediaCCC, and PeerTube/FramaTube. From the slide out menu click on the little dropdown arrow next to the YouTube name to expose them.
PeerTube instances can be added via Settings -> Content -> Peertube instances.