I've found myself having a lot easier time to learn difficult new concepts by (somewhat counterintuitively) stop trying to learn it for a week or two, then come back to it, and suddenly it's a lot easier to grasp, even if I haven't consciously thought about it since I left it.
I really relate to this. In fact, a lot of times, when working on a difficult problem, I’ll intentionally go take a nap when I feel stuck, and more often than not, I’ll wake up feeling like the problem is much easier than I thought before my nap. I can’t explain why it works so well—it just does!
With something like learning a language, problem solving skills, a code base, new maths, or wtv, it is less apparent because the mind can delude itself, and it is much harder to delude yourself with actual physical movements. You either do it, or you don't...