I apply the 80/20 rule. 8 minutes allowed, followed by 2 minutes blocked. Then at night I reverse it. 2 minutes allowed, 8 minutes blocked. Just enough time to make one search query and then get off my phone. Or if I do get trapped by something, it's only for a short time.
LinkedIn has also been especially hard to find a good blocker for to remove the sponsored/suggested posts from the timeline (it's just full of garbage engagement bait hot takes).
I just vibecoded a tampermonkey script to block scrolling on Instagram and also block reels. I also had it redirect from the `/reels/` URL to `/reel` which is just the single video view (for when friends link me memes), but it seems they removed that.
For facebook I love Facebook Purity. Only problem is it's desktop only. https://www.fbpurity.com/
Edit, some things I've been able to us ublock origin for. Like facebook reels. Not 100% clean but enough to stop them from working (no video, just still thumbnail when you open them). In some ways that provides some reinforcement learning to the brain.