How do you put 0.5 on your camera

The iPhone X does not have the camera hardware for a 0.5 ultra wide zoom level.

iPhone 11 or later models have the hardware for the 0.5 zoom level.

If your phone doesn't have a .5 camera on it, you can't do anything to add one. That's hardware. If you need a phone with a .5 camera, then you buy one which has a .5 camera.