I use NewPipe for Youtube, there are no ads at all.
I use AdGuard for blocking ads phone-wide and if I hadn't, Vivaldi has a built-in adblocker too.
Bottom line is I don't see any ads without using uBlock Origin. Original commenter is "surprised more people aren't using" it like it's the only way to go, while in reality it usable only in certain scenarios. It's best for PC but not for mobile.
I use Revance Manager for patching other apps but youtube app is shit no matter how much you patch it. Prefer NewPipe or even LibreTube over patched Youtube app.