I've heard that YouTube has started experimenting with injecting ads into the actual video stream rather than getting JavaScript in the browser to swap between video and ad. Specifically for the purpose of breaking ad blocking. (Particularly to break ad blocking on Open Source apps/clients like NewPipe.) Though I haven't seen it myself.
There are a lot of doomsayers saying that YouTube ad blocking is a thing of the past if they do that for all videos/users, but I don't think that's the case. Ad blocking will catch up given some time.