I was curious and am also experiencing the same issue as of today
So infuriating. I hated YouTube's recommendations when my watch history was on, so I turned it off and got WAY better recommendations based on which videos I liked or added to playlists. I sometimes watch garbage/uninteresting videos that I don't want associated with my account, since their recommendation algorithm is obviously dog shit and thinks watching a Joe Rogan video one time means I should only ever watch his (or similar) content. Recommendations should only be made based on what you've positively interacted with previously. Anything else is just bad for the user.
This is very annoying - I get this too now, and there is no way to make it go away (except for enabling watch history I assume). Very bad!