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"
< Părere la script-ul YT: not interested in one click
The script doesn't block anything, it's the same as clicking the item in the menu, so please refer to YouTube's help/support/feedback center.
how to unblock a channel after clicking don't recommend channel