Looking at it now, I think maybe I just found it too boring to remember the tricks, and too tedious to not make mistakes, while I found coming up with proofs more "interesting" and requiring less rote memorization.
I wish the university calculus changed the curriculum. I didn't find it particularly useful to learn how to integrate e.g. inverse trig given that WolframAlpha exists. There are lots of other examples of teaching memorization of silly tricks like that. I guess they probably do it because it's easy to test.
While I only got so far in proving stuff about a cyber-physical I was working on, but this was really fun to learn: https://github.com/LS-Lab/KeYmaeraX-release
See also: http://lfcps.org/lfcps/
I found groups, limits, continuity, fields to be much more amenable to my thinking. It felt way more similar to the things I really enjoyed (building software in scheme and C and writing exploits in assembly).
For me, I realized thst I need to write the code to accompany the maths, because it helps me disambiguate mathematical notation and put "types" on things.
It helped me a lot to work alongside real maths PhDs and realize that they have a very "intuitive" approach to maths, and don't necessarily yeet lemmas and proofs around all day, instead spending a lot of time brainstorming on the whiteboard and discussing things out, very similarly to software design. It was one of them telling me that my thinking was very mathematical that helped me "deconstruct" the fear of maths that I had built up.