Whole lotta broscience ITT.
I am surprised that Coach hasn't chimed in because this is his area.
FWIW, there is an actual term called "gluteal anmesia" where the glutes essentially atrophy because the body compensates with other muscles to achieve roughly the same goal.
Two words: hip hinge.
You'll need to start working that pattern: hip hinge pull throughs, kettle bell swings, GHR, glute bridges. Anything that programs the hip hinge pattern.
If you don't have a strong hip hinge, back squats are an accident waiting to happen in your lower back. Your squat progression should be something like: goblet squats->front squats->back squats to a box->back squats.
Anyway, like I said, this is Coach's bread and butter. Some folks (like me) squatted for years without a strong hip-hinge due to anterior pelvic tilt. It has taken me years to come close to having a real hip hinge and my ass certainly looks rounder (says my wife, with appreciation). I still don't back squat.
Get a real trainer to work with you.