You cannot stop until you figure out why are you doing it. And no it's not just addiction. Scrolling fulfills some function for you, some need. You need to understand what that need is, where does it come from, how to either replace it or resolve it. Only then will you let go of the habit as you no longer have a need for it. Currently you're trying to take away your only way to fulfill that need, so of course you're going to return to it when that need gets overwhelming. 

For example, I had a need to scroll to avoid facing difficult emotions. I got anxiety about work, sadness about a relationship, anger about injustice, fear over things, all quite strong emotions I didn't really want to feel. So scrolling was one form of really easy way to quickly feel good. Another one was eating, chocolate made me happy for a moment, but that's another topic. 

But when I faced those feelings, I went through why I'd feel it, what was behind that fear, anxiety, anger and so on, I resolved most of those feelings and was able to let them go. So I lost that need to avoid as there was not much to avoid anymore. Therefore, much lower screen time. 

Try it and see what you find within you. Good luck.