My main source of "internet addiction" (I don't completely agree with the term) was compulsively checking Instagram and Twitter. I allowed myself to do this during the pandemic because it was often my entire social life. But afterward, I found it interfering with my IRL social life. The Twitter habit was broken when Musk took over Twitter, since I was unhappy with the changes and took the opportunity to delete my accounts. For Instagram, I've found the iOS app "ScreenZen" to be great at breaking up my habit. It adds a timer before opening selected apps, giving you an opportunity to change your mind, and a timer after which the app will automatically lock again, preventing mindless scrolling. Just 60 seconds to bail out is enough to reduce 90% of my Instagram usage, and after two months of this, I find the impulse to check Instagram is almost gone.