Here are two videos that I think you'd enjoy:
https://www.youtube.com/watch?v=h5WhWu1g080 (Lumbopelvic Hip Complex Biomechanics During Squats, Deadlifts, Hip Thrusts, etc.)
https://www.youtube.com/watch?v=0fN3NhZ5Ifc (Biomechanics of "Buttwink" in a Squat)