There’s nothing quite like the unique pain of navigating an unfamiliar codebase that treats abstraction as free and lines of code in one place as expensive. It’s like reading a book with only one sentence per page, how are you supposed to understand the full context of anything??
3Blue1Brown on youtube has amazingly good visual explanations for various math concepts. Helped me out a lot when I was having trouble with calculus. It doesn’t help specifically with memorizing theorems or anything, but provides a good conceptual framework to start with. https://www.youtube.com/c/3blue1brown