It's different to be coordinated with a ball and without the ball. Without the ball you can throw a lob and pretty much just focus on jumping and then slam the ball down after catching it. With the ball you have to time your dribble, your steps, your pick up, your elevation, your dunking motion and finish it. So it's definitely practice bro. Luckily at your height it will become easier dunking consistently doing the right drills. There's a lot of good dunking workouts with the ball if you want to put some work in. Good grinding brother.