Hover a thumbnail on youtube.com and click an icon at the right: "Not interested" and "Don't recommend channel"
< Feedback op YT: not interested in one click
Well, I can't fix what I can't see, but if you could find the difference in devtools I might be able to figure something out.
This is so peculiar that the script worked for more than a year, then it stopped working, BUT only on the main account, no other extensions, different browsers, reinstalling script or versions - nothing works. Its as if google marked the account to load the homepage menu differently