One thing that jumps out to me is that his lower half is visibly slowing down as he moves down the mound. He is getting nothing from his stride and plant. His drive knee is collapsing and rotating without gaining distance to the plate. Instead of going so high with the kick and bringing it down before reaching out with an extended stride leg, reduce the height of the kick, work on flexing the back knee instead of fully collapsing it, get forward momentum from the initiation of the lift instead of waiting for the lift to be completed. Try to land on the bottom of your foot instead of the heel and it will assist in keeping you closed longer.
In my opinion, your delivery after foot strike is much better than before foot strike. You have potential to vastly improve velocity after a some focused effort on the lower half.