David Vélez on how AI let him go from one direct report to 20, and cut Nubank's layers of management in half: "AI creates the opportunity for larger span of control, less managers, much more visibility. I personally went from having one direct report to 20 direct reports over that period, because it just increases your ability to operate horizontally. We went from 10 layers to five. The easy answer when things are on fire is to just add managers to solve the fire immediately. And partly…