The "factory hitch" could be either the draw bar, or the step bumper.
Both accommodate a ball, but neither came with a ball.
Ball diameter depends on the trailer, so the buyer would supply the ball.
The drawbar is bolted to the back of the Jeep, so the ball height changes depending on the ride height.
You can look at the drawing above and see that the long bar of the drawbar is maybe three inches below the bottom of the rear cross-member.
The triangular tongue drops maybe an inch more?
Measure your ball, measure your Jeep, apply arithmetic.