Just out of idle curiosity. I went to music school and teach at a local music shop, so I'm very familiar with music theory but I'm aware that my experience is most likely not the norm.
If you are familiar with any theory (even just scales and keys), where did you pick it up? Lots of the resources I've seen both in and outside of formal education can be both confusing, and it's often hard to see the application of what you learn in the short term.
I know some basics from learning electric bass, but don't ask me about chords (beyond major and minor) or chord progressions. I'm definitely aware that this is a huge blindspot even for electronic music.
A moderate amount. I was in high school band so I got taught a little. I dove into it as one of my (too many) hobbies for a while. I can tell what a piece is doing and understand scales (major, minor, pentatonic, and blues), key signature, modes, harmony, chord progression, arrangement, rhythm, meter, chord inversions, and probably a bunch of stuff I'm forgetting. I pick it up from time to time to learn more.
However, I'm a barely competent player of a handful of brass instruments, guitar, and bass. I'm embarrassingly bad on all but the simplest of percussion. I have a hard time dialing in tone so I just try a bunch of shit and take pictures of whatever sounds fine.
Like many of my other pursuits, I know many things and never really take the time to develop the practical skills to go along with it.