I like a lot of what you do. The leg lift is behind the rubber, heal to catcher and high. Those are all power positions. Try not to let you shoulders go with your legs. You are counter-rotating. This will actually give you less body rotation.
Keep your shoulders square to your target area but do the same three elements of your lift. This will actually give you more torque. You stay closed for a long time in your delivery, that is good. Keep your tempo but speed it up at the end. If you get your shoulders right, you will feel as though a wave happens from the floor to the whip that will be created from your hand at delivery. You want the energy to transfer through your core and not around your core. You do that already.
I wouldn't change much, let you body work the way it is.
I agree with the posters who say work out. Getting athletic is a common theme with good pitchers. Best wishes on going forward.