I quit all social media (unless you count hackernews I guess), killed all notifications except calls and text messages, and regularly leave my phone in another room while I'm working or doing anything that requires prolonged attention. Helped a lot.

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.