It’s worth noting that the ad blocker-blocking is a slow roll-out. People with the same OS and browser/ad blockers will have different experiences. I’ve also never been blocked from watching but I do commonly see “Youtube is not free” dialogs pop up because I’m using an ad blocker. In my case it’s AdNauseam[0] which uses uBlock Origin behind the scenes.

0: https://adnauseam.io/