I hear you. I am not too strong in reading manuals. Videos on Youtube (and people like Paul in this forum) are more helpful.
FWIW, I go through the setlist at home and try to hear if there is a need to tweak sounds so that all songs and sounds within songs are at the right (relative) volume. (I have widgets in all song parts that let me adjust mixer volumes, along with faders using the great Awaken mixer panel: 6 Channel Template ).
But, if I notice something during a gig (or a rehearsal) and try to take a second to write a note to tweak that next time I open up GP at home.
I think during performance, you cannot devote time to that. Just adjust whatever knob you need (I just use master volume controls) and take note to fix it later.
My $.02 FWIW.