A common theme I’m seeing in a lot of “slower throwing” guys is that they don’t have great segmentation.
Proper sequence of the chain in regards to torso :
Pelvis > Lumbar > Tspine > shoulders > arm > wrist >
Proper sequence of the chain in regards to torso :
Pelvis > Lumbar > Tspine > shoulders > arm > wrist >

If any of these are moving at the same speed at the same time it is usually labeled “no hip shoulder separation” when actually you need to dig a bit deeper. Can they actually dissociate the pelvis from the torso? If no then that general movement needs to be improved first!
If yes, then there’s more than likely a timing/coordination issue that the athlete must learn to resolve through constraining or “chunking” the delivery into parts that then will eventually be blended into the full delivery once the athlete recognizes how to move it efficiently
This can also be lost if guys are sitting for extended periods of time (long bus rides) and the spine is compressed.
In short: take care of your spine!
In short: take care of your spine!
Here’s an example with @DJ_Wilkinson3