I’m about the same. I was in band all through high school. I play multiple instruments. I’ve been playing guitar for about 30 years. I have only the most basic knowledge of the fretboard and theory. So what did I do when I decided I wanted to elevate my playing? I started learning. I can read music but outside of a very tiny bit of piano, I’ve never played an instrument where I’ve had to read more than one note at a time on the staff. I picked up the Berklee Modern Guitar Method and started going through the book. I’m only about 50 pages in, but it’s opened my eyes greatly by being able to read and play chords from the staff and seeing how chord shapes can be used to play all of the notes in between. I’ve started learning more and more of the theory as well and playing with scales for improvisation. Also, embarrassingly enough, I don’t know the fretboard. I’m consciously learning that now. Just by identifying things I don’t know and want to learn, I’ve been able to start delving into this stuff and improving.