Some of the topics I struggle with right now are things like pointers and memory management. I've never had to do these things because I have historically been a web developer.
https://suckless.org/ has been a big source of inspiration for me. Because so much of what they build is simple and elegant. Purpose built. Good. The more I work on stuff like this, the more frustration I feel in my day job. Because I feel like I do is contribute more shit software to a shit software saturated world.