I know about chapter 11 it is still referred to as bankruptcy even in America.
What it does allow is to defer the debts. The people get their money eventually if they haven't been driven to bankruptcy themselves by then. And there were a few of them. It gives him time to refuse to pay, and wait for them to go under in the process. The evidence is there!
Is this a holding loophole for businesses in difficult circumstances or is it used as a performance aid. Used to sale closer to the wind and the safety net will catch you. A tactic for the cavalier, a crutch for the bullies of this world. A steel toecap against those with enough money & staying power to actually call on those debts? A lever to crowbar a percentage on the dollar?
AFAIK some of those failed businesses were sold on.

And he didn't learn those tactics at his own university, which is where now?

Outwith Trump? He takes the credit when it works! He is responsible, as any control freak is, for what & who works for him.
If it has his name on, we put the hooks on HIM.