I use multiple ad blockers simultaneously (mostly because of custom filter options, 1Blocker does a great job, for instance, of letting you choose to hide annoying non-advertising site elements [incredibly useful on the Fandom, né Wikia, wikis, for instance]). I rarely ever see YouTube ads, but I really couldn’t tell ya which ad blocker is doing the heavy lifting.
1Blocker, Ad Blocker, AdBlock, AdBlockPlus, AdBurn, AdGuard, Banish, Ka-Block, yPlayer, StopTheMadness. If I had to guess, it’s probably a combination of 1Blocker, AdGuard, and StopTheMadness. I’ve also got BlockYT, but I don’t think it blocks ads (instead, it hides YouTube shorts and can hide comments and suggested videos).
Actually, I really like StopTheMadness, in addition to blocking YouTube ads, it’ll let you set an automatic resolution setting for YouTube and will let you use the system video controls when using Safari. And that’s just YouTube centric features. It’ll do stuff like preventing websites from stopping you from zooming or scrolling, let you bypass AMP, and prevent sites from blocking you from closing tabs. Plus, you can inject custom CSS and JavaScript into any page. What’s more, you’ve got per-site settings, so you can inject custom CSS and JavaScript on one site without injecting it into other sites.