I find your personal hack on mobile to be very useful myself too - I found myself to be so much less stressed and more productive after uninstalling apps like Facebook and Reddit on my phone, and disabling notifications on nearly all other apps. When I need to use Facebook, I would go to my computer.
The desktop problem is pretty solvable for programmers. I wrote a simple bash script to add/remove blocked sites to /etc/hosts. I mapped that script to aliases 'focus' and 'distract' that block and unblock sites, respectively (requiring the root password). Finally, I set up a root cron job that runs 'focus' every hour during desired time windows (for me that's morning until late evening on Mon-Sat inclusive).
That system works exceedingly well, but I can't port it to iOS.
Right now I use Lockdown (VPN-based) with a block list and it works okay, except when I want to unlock by disabling the firewall. There's no automatic reenable option making the whole system less effective. I considered writing my own VPN-based system but haven't got around to it. Would love to see Motion tackle it.
It is not trivial to build, run, and operate a nextdns-esque service. The founders, Olivier and Romain, are some of the world's best at what they do, imo.
That said, a client-side DNS re-write solution might be relatively cheaper to implement and might even be a tad-easier than deploying an global DNS resolver with per-user custom configurations and endpoints.
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?
[0] https://www.blloc.com
[1] https://wellbeing.google
[2] https://www.androidcentral.com/oneplus-explains-how-and-why-...