On ios I use Unwatched and it is fantastic, almost as good as tubular, freetube et al on other platforms. It allows you to curate a nice upcoming ‘diet’ of just the videos you intentionally want to watch, nothing else.

Don’t know how long it will survive on the AppStore but it’s been there for a little while now.

Huh, that’s a super interesting system. If you’re 18 can you also directly go to A2 or is it all gradual from one to the next?