Professional communities with invite-only registration, where invites are only distributed to people with high ratings. Also you can add higher barriers, like a requirement to write a valuable on-topic to get rating above a certain level, regardless of the comment rating level. Basically a self-moderated narrowly focused community with invite only registration.

NewPipe/PipePipe and Freetube were affected for half a day max, these guys are super fast with the updates.