I don't think youtube is trying that hard to desperately sell stuff to you via home screen recommendation algorithm. And I agree its bearable and what you describe works cca well, albeit ie I am still trying to get rid of anything related to Jordan Peterson whom I liked before and detest now after his drug addiction / mental breakdown, it just keeps popping back from various sources, literal whack-a-mole.

I wish there was some way to tell "please ignore all videos that contain these strings, and I don't mean only for next 2 weeks".

Youtube gets their ads revenue from before/during video, so they can be nicer to users.