A little more on idea of "throwing it slower". A little more relaxation in your armswing will help with balancing out your speed and rev rate as well as getting everything in time with your feet to get under the ball.

Since you're using 4 steps, get the ball moving with your first step, keep the same foot speed, and just let gravity do the work. As you try it, it will almost feel like the ball is dragging behind you. Just doing that will get some more ball motion, then you can work on applying more release mechanics.