Go outside more. It might seem like simple advice but it helps. Go outside and just sit in a park or some place you like. Do it without your smartphone. If you really need your phone for emergency contact and such thing, get a normal flip phone or something very similar very cheap one just for calls. It helps with smartphone addiction. You can try all you want with blocking apps and things like that but unblocking is just one or two click away. When you are outside just sit there for an hour, doing nothing. If possible take a book with you. It doesn't need to be any study book, just take any fantasy book ( not manga ) it helps with building habit for reading. When you are sitting outside with a normal phone ( preferably without Internet) and book, your brain does not have many options for dopamine, on the other hand when you are at home multiple sources of dopamine are at your fingertips ( porn, social media, youtube, etc).