I compared your video to Lance McCullers. I have found another potential area in your delivery where you may be leaking energy thus leaving velocity on the table.
When both of your arms are in the cocked position, McCullers upper body is moving into forward trunk tilt. Your body is still in a very upward position. You don’t start generating upper body tilt until your arm is in maximun external rotation (when the arm lays flat). This may be due to the fact that you tilt your head off to your glove side and up in the air (look at your eyes) in this phase of the delivery. When your head tilts like that, your trunk is sure to follow thus - losing energy to the plate. In the bullpen video you sent me, the lower half looks good. I believe its your upper half that you have to work on. Keep your head and eyes on your target. That should straighten out the upper body tilt and help you move into forward trunk tilt.
***Side Note - just looked at the video in the garage again. In that video you you keep your head and eyes on your target. What I see is you try to hard to to rotate the lower half. In doing so, you rotate too early. If you take the upper half in the garage and put it on the bottom half of the bullpen, I think you will be there.