Years ago a $9.99 el cheapo Walmart DVD player was my first USB media player on an old CRT TV.

Custom launcher like Wolf Launcher,Yes. Not a custom ROM.

+1 on that.

But…by the time you put together the bill of quantities for the Pi, Case, Power brick, Active cooling, remote… The 1080p Firestick becomes cheaper. The Firesticks advert filled UI can be wrangled using a custom launcher.

That makes sense, comments are an issue with NewPipe. Please open an issue on the NewPipe GitHub about that and the watch-later list.

The functionality will only get added if users ask for it. The idea for NewPipe in the beginning was a light-weight YouTube frontend with offline subscriptions ( i.e. no need to login ). Bits and bobs got added as and when user requests came in.

For the phone the easiest way is NewPipe with Sponsorblock https://github.com/polymorphicshade/NewPipe

One step above it , slightly more involved is ,YouTube-Revanced. The step by step walkthrough is in this thread, no command line stuff just follow the steps religiously. https://www.reddit.com/r/revancedapp/comments/xlcny9/_/