Same for me, when i use youtube on my mobile i am flabbergasted by the amount of ads and 20 minute promo programs. Why and how can you watch that without a add blocker?
If you're on Android, there's NewPipe, a fantastic YouTube client that brings all the benefits of YouTube Premium: no ads, downloads, listen with screen off, and picture in picture.
NewPipe also supports other services such as SoundCloud, MediaCCC and PeerTube right out of the box. The killer feature for me is that you can make up playlists containing media from different sources (which I use for playlists containing music from both YouTube and SoundCloud).
(I'm not involved in NewPipe, except being a very happy user).
I don't get any ads whatsoever on YouTube with uBO. What I do get is about a 20% chance of something screwing up in the ad blocking process for prerolls and getting the grey "there was an error" screen instead of a video. I just hit reload and the video starts playing.
Slightly annoying, but I don't utilize auto play, so I don't have to worry about it stopping my playlist or passive watching.