This is my experience, and I need to preface it with this: I don't manage this perfectly, i just know the strategy works when i execute it:
First off, you need to have some awareness of why you form routines and habits. If you're sober, you get dopamine largely from external activities, and engaging activities. Things that stimulate, beckon you to give input - you mention gaming and painting (same tbh) - Why do you think you're so connected to gaming? It's stimulating. It needs constant input, engagement, it's flashy, it's engaging almost all of your senses and your thought capacity in a totalizing manner - this is hijacking your reward pathways. It may not be as ruinous as, say, recreational drugs can be, but this is still addictive; even if not, it's certainly habit forming.
You mentally need the tools to deny yourself. Not to become a monk or ascetic, but things like mindfulness and meditation can help because they train you to pull back from external stimuli and engage them differently. If you do this, once you start detaching, I'm telling you, your mind will start to re-order its own priorities and deprecate cheap thrills.
Cultivating a sense of joy in learning and experiencing information in your internal world isn't that difficult, but you need to sort of make sure that other stimuli are set aside. I will turn my computer off and leave electronics out of my reading space so that no vibration, no alert, nothing will ask me for attention - there is so much bullshit calling you to attention that makes a passive activity like reading extremely hard to do.
you can think of your relationship to the world as something inside a meatsuit that is raised from birth to react to what's outside it. If you do not question or manage this relationship, you will always be pulled outside of yourself by the most engaging/pressing/conditioned thing in your environment.
This is a lot of words without even getting to the task of reading, but this is the stuff that I personally had to internally wrangle before I ever found time to start reading and self study again.
You can rewire yourself to find pleasure in productive tasks. Eschewing marketed entertainment for skill and knowlege building sounds boring, but once you've trained yourself to get dopamine from those things it just becomes a new normal.
You're gonna have to find the discipline to construct a new routine that devalues something like gaming and replaces it with something like reading, and in 2025 that's not actually easy.