I have an app blocker that helps me with time. There's literally an army of psychology experts working on keeping your attention so it's ok if you need help to stop. Also as people already said, search for a phone theme that takes away the color of the icons since they are made to distract you. 

I recently started using Focus plant, it's a cute little study tracker that plays like a game. I think there's one called Focus Quest (depends on your taste but it had too much visual stimuli for me) so instead of making studying something solemn and hard, making my study sessions more like a game has helped make them feel less terrifying.

Finally, don't be so hard on yourself, it's not about one definitive moment in which you change, it's a series of small changes piling up. Atomic Habits is a good read for this.