This triggers the rules he has to control the ball. When you see the video, as I posted, and you see the point of the ball that was in the crook of his arm move to a point where the point of the ball was straight up, the ground caused that and the rules are specific. All the rest of your argument might be correct, if.................the ball didn't move when he hit the ground because of the contact of the defender and him falling and the ball hitting the ground.
The ball was pinioned between his hand and the crook of his arm. The ball left the crook of his arm, moved by the ground.
There is no regains control once the ball is moved by the ground.
At what point? - you ask.
When the ball flew into the air after hitting the ground this is indicative of the ball being out of his control. And that started when the ball was dislodged by the ground. and coming loose to fly above him when he rolled over.
Start at the 2:00 mark where it is in slow motion. You see the pylon and Dez hitting the ground and the ball shift.