Reddit reviews The Forrest Mims Circuit Scrapbook, Vol 1

Learn from as many different sources as you can find. I recommend Forrest Mims's books (one) , (two) , (three)

Beware that most SPICE simulators focus on very simple 2-terminal and 3-terminal electronic devices: resistors, capacitors, inductors, transistors. But in today's modern world, we design electronics using VLSI integrated circuits, and these are seldom available as SPICE models.

So you will be able to SPICE simulate transistor circuits like the winkie-blinkie thing you built years ago. You'll be able to SPICE simulate opamp circuits, and 555 timer circuits. But not much more, because you won't have the requisite simulation models. Eventually you'll have to build real circuits in the real world and test them out in reality.

If you're an experienced software engineer then you can handle the calculus-I level math needed to understand "real electrical engineering" as practiced by non-hobbyists. After you get somewhat up to speed designing and simulating and building circuits that work (say, in 9 or 12 months), you can start to read college EE textbooks and begin to understand what SPICE ".AC analysis" actually is & why it's useful. You'll learn what SPICE ".FOURIER" is good for, and what it isn't. And so forth.