Hi Annette- so much of your post resonated with me and reminds me of my 4.5 yo son- he too is creative, did extensive pretend play at an early age and continues to struggle to find peers in his age group who have the same imagination/play ability.
He really needs an understanding 7 yo to do complex pretend play for a couple of hours daily

LOL - which means he plays a LOT with me and his favorite babysitters and copes with, but does not love preschool. He is benefitting from preK- just to help him learn how to get along in a group of kids with varying skillsets, to actually sit in circle time and participate in the crafts. BUT, I sense his frustration and feelings of being different than the boys (even older ones) in his class who still seem to prefer crashing cars than real imaginative, cooperative play.
Hugs to you- I am actually eager for Nick to start kindergarten where he'll have MORE kids to choose from and I already see him getting along better with many of the girls who seem to be more into pretend play at this age...