My method: I subscribe and upvote generously, only downvote when it feels good, and do "not interested" in the sidebar recommends, with prejudice ("I don't like the video") if necessary. But the real trick is, on the yt home page, if any video that even looks like content I don't like comes up, I choose the option "don't recommend any more videos from this channel" immediately.
Only in this way have I managed to completely expunge all mention of J**dan P**erson from my yt recommends.
This sounds like the Google News problem - there are more trash blogspam news pages found by Google daily than you can possibly ignore. I've stopped using it entirely because of this but just today it's showing stuff from "Cool Material", "Reality Tea" and "BreatheHeavy.com" (not to forget "Minimalist Baker").
Only in this way have I managed to completely expunge all mention of J**dan P**erson from my yt recommends.
Completely!