I have a CS/applied math background, my main job is software development, so I don't have problems with the software part. If you are interested in compiler design specifically, you can find a lot to read or to watch online.

When building my system, I was inspired by 8 bit retro computers like ZX Spectrum. Their architecture is straightforward and easy to understand.

Electronics just fascinates me, but I can't really point out a single source which gave me the insight. A lot of playing around with transistors, microcontrollers, logic gates gives the intution how to design stuff.