I think you need to look at your sleep pattern.

As well as having focused study time without distractions. So not studying behind your computer where you are supposed to have fun. But many in the library at uni. I don't do this myself, but I know many students do this to avoid distractions. For example because they have fun cool room mates.

I always feared I multitask behind the computer too much, open too many taps, and that that would destroy my attention span or focus. It has not. But that is just my innate neurology. For most people, it is a problem and it takes awareness.

Overall, the situation you describe here is rather 'simple', as in; you know the problem and you know how the solution should look like. The problem is actually doing it. For that, I have no advice. I have alway studied completely chaotically. It didn't work for me in the past. It worked for me great right now.

I have been in a situation where uni staff have really tried hard to get students to make a schedule, adhere to it, avoid study-avoiding hehavior, create a study-friendly environment. These kinds of challenges. But that's my fellow students that were struggling a bit. There are all kinds of formal methods about how to study in a disciplined and structured way. Since you are struggling, this is where you should look. And find the advice on how to implement that works for your pitfalls/inclinations.