I've been saying this for years - those flashy two-ball drills where players are bent over pounding the basketball into the ground are completely overrated! 
Real handle comes from footwork, foot speed, and foot nuance. If your feet are planted while you're doing stationary dribbling drills, you're wasting your time. 
Kobe didn't have some secret trainer with magic sauce - he put in the hours and figured out exactly what his skill set needed. The best players develop through intelligent work, not just mindless pounding. 
Stop doing drills that look impressive on Instagram and start training movements that actually translate to game situations. Your handle will thank you later.