Rocketblocks is great for math/charts/exhibits, but horrible for structuring/frameworking. Please stop using it for frameworks!
In terms of how to improve, I genuinely recommend coaching. Frameworking/structuring is the hardest part of casing and is really what training/coaching all comes down to (it's about 80% of what I work on with candidates).
Look, it's not easy, but think of it like tennis. You need to learn a new grip, practice practice practice, and keep fixing your grip until you can hit well.
Best way to do this to get a trainer and a practice buddy (coach and case partner) and iterate iterate iterate!
Struturing Mindset - How do I use frameworks in a case?
If there's anything to remember in this process, it's that cases don't exist just because. They have come about because of a real need to simulate the world you will be in when you are hopefully hired. As such, remember that they are a simplified version of what we do, and they test you in those areas.
As such, remember that a framework is a guide, not a mandate. In the real-world, we do not go into a client and say "right, we have a framework that says we need to look at x, y, and z and that's exactly what we're going to do". Rather, we come in with a view, a hypothesis, a plan of attack. The moment this view is created, it's wrong! Same with your framework. The point is that it gives us and you a starting point. We can say "right, part 1 of framework is around this. Let's dig around and see if it helps us get to the answer". If it does, great, we go further (but specific elements of it will certainly be wrong). If it doesn't, we move on.