I tried something similar and the results are a mixed bag at best. When the algorithm decides to recommend a video from a creator that I don't follow, it is usually something worth my time. However I cannot seem to stop getting recommendations for videos I have already watched despite diligently clicking the "not interested because already watched" boxes.

A lesser issue is that if I don't watch the videos from a certain channel or genre for a while, the algorithm decides that I must have lost interest and stops recommending those content altogether when that's not really the case. And the "related videos" on the side bar never goes beyond a list of videos from the same channel.