I recommend reading "Digital Minimalism" by Cal Newport. It identifies this problem well and has a lot of practical suggestions for countering it. The one that worked for me was uninstalling twitter/reddit/HN apps and replacing them with using the browser. Doesnt sound like much but the added friction of typing out everything in the browser (I'm mostly on incognito) took my compulsive dopamine-fix phone-checking behavior down by a lot. For HN, I also try to rely on the "Hacker Newsletter" to counter any FOMO.