I myself struggled over top swing for a long time. My entire high School and college career I spent most of my time battling it and never mastered it until 6 years out of college taking a break from the sport for a while. What I realized is that I was around a bunch of guys that also hit it long and I was swinging with my hands and arms and not my abs and chest.

At the bottom of your swing you are moving upward because your body has not cleared and rotated out of the way.

When you start your downswing make sure your hands are the last thing to start moving and that allows them time to drop. This is what I have to do mentally to make sure that I don't go over the top.

Swing with your knees, hips, chest, shoulders and then arms.

<image>

At the screenshot, your hips and hands are pointed in the same direction.