Greasy Fork is available in English.
Hover a thumbnail on youtube.com and click an icon at the right: "Not interested" and "Don't recommend channel"
< Spätná väzba na YT: not interested in one click
The new 1.1.6 should fix it. I guess you were using the inline preview player, which I always disable in account prefs.
Used to work fine, but yesterday it stopped.