Does this work? I've been doing that for some weeks now, nothing has changed about my home page.

It is more important to scrub your history and upvote.

You can use ublock to remove the sidebar completely

In case you start watching such a video (and maybe in general), it’s probably more effective to downvote it and remove it from your watch history. And when you use “not interested”, there are two “tell us why” follow-up options “already watched” and “don’t like”. Selecting the latter may be necessary for “not interested” to have a stronger effect.

I don’t know if YouTube Premium makes a difference, but I don’t see highly clickbaity thumbnails very often.