In econometrical terms it would be "double causality", as it forms a vicious cycle. Using your phone to self-soothe leads to not developing real hobbies, which leads to more isolation, which leads to more phone usage.
Say you decide you're now a chess person. Instead of doomscrolling before bed you find relaxation in the meditative study of chess games for an hour a day before going to bed and now you use your phone only as an alarm. You join your local chess club to play IRL during weekends and attend some classes too. What were the effects? Well, there are the proven long-term cognitive benefits of learning and practicing chess, there's the immediate cognitive and emotional benefit of a larger social circle and a community, and medium term you'll feel good about yourself for achieving milestones (getting to 1000 ELO, winning the weekly tournament, etc.)
None of that would have happened if you had stayed on your phone. You probably already invest just as much time on it as you would in chess in this scenario, but it has no ROI, it is designed to suck you in.
Say you decide you're now a chess person. Instead of doomscrolling before bed you find relaxation in the meditative study of chess games for an hour a day before going to bed and now you use your phone only as an alarm. You join your local chess club to play IRL during weekends and attend some classes too. What were the effects? Well, there are the proven long-term cognitive benefits of learning and practicing chess, there's the immediate cognitive and emotional benefit of a larger social circle and a community, and medium term you'll feel good about yourself for achieving milestones (getting to 1000 ELO, winning the weekly tournament, etc.)
None of that would have happened if you had stayed on your phone. You probably already invest just as much time on it as you would in chess in this scenario, but it has no ROI, it is designed to suck you in.