Greasy Fork

It seems to work with m.youtube.com, but you have to change the match pattern to *.youtube.com.

Thanks for the feedback! Yeah, I forgot about the mobile version when I changed the matching pattern in v2.1.
But I wouldn't recommend *.youtube.com since it will break https://music.youtube.com/
Tracks will have no album art and some other issues might occur.
Anyway, I updated the script to v2.2 to support the mobile version. It's better to have separate matching rules.