I played classical for years as a kid, then played any songs I could get my hands on - folk songs, pop, Beatles etc. So I learnt basic chords and how they work by playing that stuff a lot. Then when I got into jazz, you learn by listening and transcribing. Transcribing tunes, solos, chord voicings, anything. All different instruments. I've transcribed piano, trumpet, sax, guitar, bass, drums.. and Indian classical, funk, reggae etc. Anything you hear and like but don't know what it is, transcribe it, and learn to play it yourself. (If it's simple enough, you don't need to write it out) You learn a lot of things by doing that. There are books of transcribed solos, I think they're absolutely worthless. Do it yourself. Besides that, books of songs, solos etc always have mistakes, sometimes a few, sometimes thousands. I've written out orchestral scores to play on piano, studied those. I studied/played/sang Debussy's opera for over a year, that felt like a complete musical education, a lot of it is simple combinations of notes. In my 20s I learnt a lot about what pianos can do by playing a lot of piano pieces by Debussy, Ravel, Rachmaninov etc. Also playing other instruments is good - I've spent a fair bit of time playing drums, bass, guitar, trumpet, trombone, clarinet, etc. Also learning who the great musicians are is invaluable, so you can find who appeals to you most. Check out a lot of different stuff. Study, analyze, learn from the music you listen to and love. All that is so much easier since the internet! (I started in the 80s) It should all be a great joy. I enjoyed every minute of it.
The authors do a nice job of introducing basic (and then advanced) music theory concepts with text and audio/video examples using recognizable pop songs. They also have some tools for exploring themes further on their website.
I've read the books a couple times and it has given me the ability to reason about existing songs as well as better compose and improvise with songs myself.
Definitely agree about the guitar practice being better than PT part. :)
https://www.musictheory.net/lessons will pretty much teach you what you'd learn in two years at university. Honestly, I find it the best resource to get up to speed on common practice period music theory.
I spent a lot of years learning guitar technique while not progressing much on the music theory side until I started reading Mark Levine's Jazz theory book. It's probably the best material on music theory I've read, though it's slightly based on jazz, or at least references it a lot. But I think you could use it as a general theory guide.
Another favorite of mine is Yusef Lateef's Chord and Melodic Patterns book, though it's more advanced/exploratory.