Here's the throw that got me looking into it:
That's spin rate, man. That thing noses over and has so much spin/velocity on it that it doesn't slow down. For most QBs that nose will just kinda roll over when it's reach it's apex and it will meander towards its end point. But Mahomes' ball is still spinning like a top so the nose pulls over hard and it continues to travel almost as well as it was traveling when it left his hand. So the thing just divebombs towards it's receiver.
And Mahomes control of his instrument is the only thing that makes him aware of how that ball is going to behave when he releases it. You give anyone else the ability to do that and it would take 2 years for him to figure out how to utilize it. They'd be expecting 'normal human being' flight paths. Mahomes knows how his ball works and how to use it so he can do shit like that when nobody else could even with that kind of arm strength.