From the video, It doesn’t even look like you are trying to throw that hard. If your throwing 88 mph now and can get more momentum towards the plate and rotate faster then I think you can increase your velocity quite a bit. In engineering the term is called the priciple of relative velocity.
The example is that if object A is traveling 80 mph and then object B is propelled from object A at 20 mph in the same direction, then object B is really traveling 100 mph (neglective wind resistance).
The same is true with your body to a certain extent. Although it is not a perfectly efficient system, if your increase the rotational velocity of your pelvis and torso then you should inherently increase the rotational velocity of your arm without accerating it any more than normal. This constant acceleration means no extra force, only extra velocity.