So... don't install those apps?
I guess that's easier said than done. I keep an `/etc/hosts` list of distracting websites (includes HN) and route them all back to my hobby trello task board. Message to myself being, "hey, distractions from work are fine, but wouldn't you rather be working on one of these things than screwing around in a comments section?" And I have a shell script that will wipe a given line of the /etc/hosts for 30 minutes in case I decide "nope, I really do want to screw around in the comments section this time."
Maybe someone should build an app that does something similar -- redirects you when you try to either visit or install fb/twitter/tiktok... not sure if possible without jailbreaking or using an alt app store, though.