App blocking does not work. Delete the apps from your phone that you do not need. That usually means "all social media but youtube". Turn off autoplay/autoplay next on Youtube. On desktop, I actually use LeechBlock to even block youtube during work hours. It has a feature that blocks any override for specific sites or sets. If I want to use youtube, I pull it up on my phone. I play the video while putting my phone propped up on the kick stand on its case, next to my laptop.

Seems counter intuitive, and a recipe for distraction. But it works. With autoplay off, you have to manually pick up your phone and select the next video.

Podcast apps are a great replacement for youtube to play in the background. I use Pocket Casts, but I am grandfathered in because I bought it before they went subscription. I can't speak for the free version. If you are Mac/iOS, Apple Podcasts is now very good. It is also available on the web for Windows/Linux. The default option on Android is Youtube Music, which is a disaster. I would recommend Pocket Casts there. The free version can't possibly be worse than this. Pocket Casts is also available on web/desktop so your listening can sync.

I understand that you think you will eventually bypass these barriers, but this belief leads to failure. And the only way to move forward is to believe you can follow through.