Not exactly your main point, but where’d you go to learn calculus? I did the usual classes in high school but none since, and I’d love to develop a better appreciation for it.
My suggestion is using Khan Academy if you want to better your math knowledge. It's really quiet good for that sort of thing. It was just starting to take off when I finished my degree. I wish it was available before then.
I learned way more reading crafting interpreters than I did in my compiler class for example.
But I also do read textbooks for fun… Now that I have a few decades of experience in a lot of these subjects I get way more out of the books. And I can start to understand more of the meta information. Like, of all the things the author could’ve used as an example, why did they pick that. Also, it’s hugely interesting for me to look at the homework problems and theorize why this particular problem was picked. Especially fun for electrical engineering books. But ya, I’m weird like that.