I learned my modes back in the day but never had the knowledge or ear to use them properly. My chops are gone, along with my calluses . I only get a few minutes a day, if that these days.
I try to play some fusiony stuff to backing tracks- sometimes its ok, other times it sucks. And I have no muscle memory at all so Learning songs is a nightmare. Im keen though.
I'm fine with learning the modes and the shapes and makeups, but it's more how to use them properly over what chords and in what situations. Saying that, learning their relative keys is tricky and something I never fully memorized.
I think over the years playing mostly metal I fell into the trap of just leaning the basics and playing along with the specific key, then using my ear to add passing notes and whatnot to make things interesting. You'd cover major, minor, harmonic nimor, some diminished, blues, pentatonic, even phrygian and phrygian dominant with metal and they are relatively easy to use knowing the style, but I fell into that trap and learning the basics and not really studying chords, and exploring using scales and modes effectively over those specific chords. I think that's where the jazz stuff comes in where they play more over the chords progressions as opposed to a set key. That line of thinking makes you look at the fretboard in a totally different way.
The basic knowledge I have would be following metal guys, like I said you can look at Criss Oliva and someone like Chris Holmes who like the Dorian mode, even though they probably aren't using them properly over the chords progressions they are using.
I guess I should go back and study more Satch and Vai. It's funny, my exams when I did my gradings I played Circles for one, Crystal Planet for another and Love Thing for another. Nailed them but it was only years later that I understood what was going on. Even Crystal Planet has some cool different stuff in that solo. Probably should start with Lydian and listen learn Flying in a Blue Dream lol.