I'm doing the same thing except YouTube and certain niche subreddits have been very hard for me to kill off. Also apps that I want to check up on every now and then get put behind a firewall so they can only access the network when I allow them to, but some are still able to send me notifications despite being blocked. I need to figure out how they are getting around that or better yet just uninstall the app. After I killed off all the big tech social media slop I found notifications for random things to be almost as bad.
I kept YouTube as well, but I tend to use it more as a podcast app then a video app. I try to only listen to it when I'm doing other stuff like doing dishes or walking the dog.
That's interesting that you have problems with notifications. I'm on Android and if I turn them off they've pretty reliably stayed off. I don't even get notifications for emails. Just calls, texts, and a few important ones like my credit cards notifying me when they're used.