+Mark E It does look like there isn't much arm rotation, so the trail hand is on top, maybe a bit too much. You'll want that lead elbow pointing more out instead of down at the ground. Try the "turn and grab" drill. Don't worry so much about the centered pivot idea, but focus on the idea of where the palms face - https://golfsmartacademy.com/golf-instruction/turn-and-grab/
As far as the foot. It looks like your pelvis is rising and knees are straightening immediately during the transition. This can happen from the quads getting active too soon. It's more of a quick impulse of force instead of a gradual build in transition.
The foot sliding backwards is normal. That's the direction the foot should travel if for some reason you lost friction. In your case, it's losing friction because the pelvis is raising when it should be lowering.