How to enable gravity only on the z-axis

I have an item heal box that the player can pick up. The item is a blueprint that contains static mesh, sphee (collision) and rotation movement.

It works fine when I place the item in a level.

However, I also want the item to drop from enemies.

How do I make the item have gravity so that it only falls along the Z axis and stops a few centimetres above the ground? Without somehow rotating in different ways during the fall/impact?