Having also spent many years as a composer-arranger-orchestrator and producer has served me well as a guitarist. Because I see myself as a “writer” first, I have used many techniques learned from writing and producing in my guitar performing work.
Know this: Playing an instrument is as much mental as it is physical.
We performers (especially us guitarists) tend to forget this. We usually are impressed by the physical aspects of playing guitar.
I have taught guitar for many years and have frequently seen what I call a theory phobia.
It is vital to know that your hands work about as good as what your head knows. What I mean is how music works, which is basically what Theory is.
How much you need to know will depend on your goals and is in relation to the styles you want to master. Mastering harmonic techniques for Folk or Popular music (i.e. most contemporary worship styles) will not, in most cases be as complicated as if you wanted to master Jazz, or 20th Century Classical harmonic techniques.