increase speed into and through the leg lift.
This is the source of velocity. What you do with the first motion will aid in force production later in the delivery. Look to explode into your lift and away from the rubber in the direction of home plate with as much force and velocity as you can produce.
stride on the centerline based on your position on the rubber, not on the centerline of the rubber itself.
Currently, you are setting up on the left third of the rubber, and your landing foot is across the center line. Lower half is traveling left to right and your upper half is traveling right to left (fighting against each other). Your upper body energy is partially being used to stop your lower half from heading toward the RH batter’s box. Instead of spending that energy to change your path, bank it for use in the pitch. Let the energies combine vs. canceling each other.
keep your glove side involved longer
When you drop that glove to your side you are limiting the length of the lever and limiting your body’s ability to rotate your shoulders around your trunk with power.
get some passion and intent to throw hard into your entire delivery
Your delivery lacks intent and power. This delivery, in its current state, reminds me of someone spending a lazy day casting stones out onto the lake. Let’s see some fire in your belly.
There are some things to work on later in the delivery as well, but focus on the start for now.
Steven makes some great points that are similar to what I saw.
If you get moving linearly in the proper manner, after release of the ball, your entire body will be together on the same line and you will have more flexion automatically. When you can add your core strength into the beginning of this flexion, all that energy is added to what you have already produced and directed toward the plate.