This is a big reason Google wanted to push the whole “web integrity” thing. There would have been no way to use an adblocker after that and they would have won the blocking wars. It’s bad enough they’re gimping Chromium with Manifest v3, but they tried for it all.
Adding that stuff to Android, so if you don't have the genuine YouTube app the server won't even serve you the videos. It is meant to kill things like ReVanced.