Since you're asking for it, a request that I have is if there was a mobile-OS wide implementation of it, that'd be great. I've tried launchers like https://getsiempo.com (defunct?) and https://lessphone.app but walked away unimpressed due to a variety of reasons: The main one being having to change habits to adopt to the new UX, whilst solutions like blloc [0] look appealing from far-out, they need equal amount of buy-in. That said, I am all for zero-config solutions.
A personal hack, I want to share: I exclusively use distractive websites from the browser (no installing "fast", "always-on" apps), and I force clear cookies everytime tabs are closed.
That means, I'm forced to login to view any new comments, likes, messages, or notifications and that is enough of a detterent and an annoyance that I don't feel the urge to seek validation often by rechecking on number of upvotes, likes, or replies of the trails I leave on various social media websites like news.yc (which is amongst the cleanest social media websites out there, in that it doesn't employ any dark patterns to lure you in, but that karma count must keep going up, right? #growth-mindset).
Coming back to mobile, on Android, Google's digital well-being initiative [1] has help kick-start competing implementations. I particularly like OnePlus' version of it-- the Zen Mode [2]-- It requires no setup or configuration and simply learns to know what's causing distraction, shows you a pop-up warning about too much usage, and if enabled, it simply goes nuclear and denies access to the phone for 20m.
I'll keep an eye-out for Firefox and/or Brave versions of Motion. Any idea on timelines for those?
[2] https://www.androidcentral.com/oneplus-explains-how-and-why-...