There are several pieces I will give credit to for this. First a split between old and and new ownership; old for the new training facility. New for creating a better environment, and also welcoming Dunn to the organization. Dunn was so enthused to be part of the org and promised Ishbia that he would be in the gym full time.
KD and Book; who wouldn't want to play with these two?
Coaching and the FO, coaches can ruin a players psyche at all levels of basketball. Most do so by promoting the wrong players, it happens a lot! Bud has put him in a spot to succeed and use his skillset accordingly. And the FO for putting a coherent team together this year.
Last is Dunn, he put in the work, that says a lot about his motor. He didn't get the opportunities he is getting now, and his college coach didn't see that he had that something extra in him to become a better player. He's getting more reps than he ever has and it is showing.