As a n=1 data point I'd like to add that I watch youtube mostly for music, and it that sense the algorithm is not so bad (since there isn't much room for "viral" clickbait), and my only complaint is that it usually shows me the same videos over and over, but it still shows me related videos that I usually like. Whenever I commit the mistake of clicking on a non-music video, my recommendations get polluted for something between one day and one week.
I never log in, so if for some reason my cookies get deleted or corrupted I suddenly get a fuckton of shit with celebrities, "outrageous" political opinions and so on. The recommendations don't get back to normal until at least 3 or 4 weeks. This has happened 2 or 3 times, and it's so infuriating that I wonder if youtube does it on purpose to nudge me into logging in and have a view history associated to my account.