One trick I have is if I see a video in my sidebar on YT that I don't want to taint my profile, I copy the url without going to it and open it in mpv directly. I tend to watch all my videos in mpv, but I do usually like to have them in my browser history and save them to playlists to find later as well, so I'm just skipping that part. I don't know if this method is perfect, they should still see my IP, but anecdotally I think it's been fine.