Too add to Coach Baker’s observation, this is what I also see. I like the beginning of your delivery. Good early weight shift (while getting gathered/loaded). Leading with the hips. Momentum towards home plate before hand-break (not a must, but a good rule of thumb). Stable and engaged with the back leg. The center of gravity and hips lead the action.
You lose velo in the next phase of the movement - You kind of stall out after hand break. You begin this part of the movement by sitting back into the stride and engaging the back leg, but then you become vertical, more upright. You have to keep your back foot planted as long as possible utilizing ground force enabling you to move your core down the mound while sitting back into your stride. In other words, your hips and center of gravity should be dipping WHILE moving towards home plate. See pic below
Second, because you are not keeping your back foot totally engaged with the ground, you lift your heel up prematurely which engages your front leg to open too early. Lifting your heel early forces your quads to do all of the work. By keeping the back foot planted on the ground and sitting in your delivery, you will be engaging your glutes instead of your quads. See pics below
This is why you look so vertical in your delivery and can not get your chest over your front plant foot. See Coach Baker’s picture
Finally, because you delivery is too linear, your plant foot heel lifts up carrying you down the mound
If you clean up what I just talked about, you will find the hidden velocity you are missing.
Hope this helps,