I used to have the same problem. I used to sleep around 2-3 am. I tried everything from turning to a strict schedule to putting phone in a different room but none of it worked. Then read about Chronotherapy where you delay your usual sleep time by 3 hours every day for a week until you reach the desired time then you stick to it.
https://en.m.wikipedia.org/wiki/Chronotherapy_(sleep_phase) Now I go to bed around 10:30 and it has vastly improved my wellbeing.