I used to use NewPipe when I had an Android. It was great for "subscribing" to creators without needing a Google account. Youtube kept breaking it. Don't know if it still works. https://newpipe.net/
and I don't get why the NewPipe devs are against upstreaming it... kudos to polymorphicshade, updates in NewPipe get handed over pretty fast.
Personally I would've just been fine with them saying that it's feature creep and maintenance burden they don't want, I'm sure newpipe is already more than enough work to keep up with in it's current state, but there you go.