I only discovered NewPipe recently and it's a really great app. For those unaware NewPipe is an alternate YouTube app on F-Droid which has loads of nifty features such as being able to play the audio of videos in the background so you can shut off the screen. It will even handle subscriptions for you without any sign in.
https://newpipe.schabi.org/
https://f-droid.org/en/packages/org.schabi.newpipe/