I'm surprised to not see Pascal's quote in this list:
"All of humanity's problems stem from man's inability to sit quietly in a room alone"
...but maybe that better sums up OP's issue rather than a solution.
Either way you'll need to take steps to make it harder to do the things you're currently doing (e.g. get a dumb phone, set up a firewall rule to block these sites, set a timer) but there might be a deeper underlying issue of having nothing better to do.
Perhaps making other aspects of your life more difficult will eat up this idle time while also providing more fulfillment. I've personally found that riding a bike to get food at some place farther away (as opposed to eating at home, ordering food, or just driving somewhere) is an excellent way to detach digitally, get some exercise, and force yourself to see new parts of your town/city. Obviously this doesn't work for everyone but the gist of this is to force yourself to take time to do something unexpected and difficult and find your reward in that instead of reading every HN thread, checking every email, and responding to all the memes your friends send.
One of my favorite pastimes (which allowed me to have a more fruitful relationship with my computer): Living in the Santa Cruz mountains, sauntering in the woods, swimming in a creek, basking in a meadow, biking down into town for coffee and bookstore scouring, and taking the city bus back up. It's just not the same in the Los Angeles greater area.
I experienced the closure of The Literary Guillotine, the small, academic bookstore, in the fall of 2019. But on the other side of the same block, there's Bad Animal[1], a small bookstore/restaurant: they have an incredibly impressive used selection - it was my go-to spot.
There's wishing the town returns to being affordable because high costs only rids places of their proper energy. Despite being in my mid-twenties, these days I, maybe foolishly/naively, dream of living in Bonny Doon.
"All of humanity's problems stem from man's inability to sit quietly in a room alone"
...but maybe that better sums up OP's issue rather than a solution.
Either way you'll need to take steps to make it harder to do the things you're currently doing (e.g. get a dumb phone, set up a firewall rule to block these sites, set a timer) but there might be a deeper underlying issue of having nothing better to do.
Perhaps making other aspects of your life more difficult will eat up this idle time while also providing more fulfillment. I've personally found that riding a bike to get food at some place farther away (as opposed to eating at home, ordering food, or just driving somewhere) is an excellent way to detach digitally, get some exercise, and force yourself to see new parts of your town/city. Obviously this doesn't work for everyone but the gist of this is to force yourself to take time to do something unexpected and difficult and find your reward in that instead of reading every HN thread, checking every email, and responding to all the memes your friends send.