I think there are three main levels in the approach to hobby electronics: 1: do it as the book says so it will work, 2: build experience also by making modifications so one can know in a pure empirical way why it does or doesn't work (for example using an electrolytic cap for RF decoupling), and 3: learn the theory behind parts and how they work, in order to be able to design from scratch or make heavy adaptations. 1 and 2 require time and will, 3 requires also math knowledge, and can be slow to conquer. I have personally been stuck too long time at 2, and now am still somewhere like 5% of 3, which all things considered is not bad at all.
It's a myth that electronics design is math-heavy, because you can do it with pretty much just +-/ and some ² and roots. Even for e.g. filter design you don't actually need to be able to do (or even understand) any of the calculations yourself, because tools automate it away. Analog design with "basic blocks" is pretty straightforward, "free form design" not following basic blocks (usually resulting in part count reductions or performance enhancements) is much harder. The latter is what often produces "trick circuits" which most people cannot analyze on their own and possibly cannot analyze using SPICE.
