I can't code, but if y'all need a tester, let me know. I've been using this app (the sponsor block one if that makes a difference) religiously for almost 3 years now, and it does have some annoyances.
Yeah, they don't want sponsorblock. From what i understand they think it hurt youtubers so they don't want to implement it. The one you use is an unofficial fork. With this new version, the dev would need to do all that work again.
YouTube playback issues will occur every so often, even after the rewrite. They're not using the official YouTube API and rather scraping youtube.com, to avoid what happened to Twitter and Reddit apps.
Downside is, if Google changes the YouTube webpage, there's potential for breakage and NewPipe needs to be updated.
Did you try updating it? About 1mo ago a fix was rolled out to patch out a change Youtube made that broke the app for everyone, videos would either not play, or stop playing after a minute or so