GrabAimPosition Not Aiming at Screen Center in Horizon Worlds (Desktop Version)

I recently ran into this problem as well and had to experiment to get the aim as accurate as I could to that center dot. Problem is that this changes depending if you are using the 1st person or 3rd person camera. I decided to force 1st person view and on the grabbable with the projectile launcher gizmo facing exactly forward and turning on Use HWXS Grab Anchor I found that the HWXS Anchor Rotation that worked for me was -5.50, -7.00, 0.00. If you want to use 3rd person camera you will need to experiment with this rotation to figure out what works best for you.

After you change the settings, turn that grab anchor toggle off and back on again. I have to do the same thing with my VR grab anchors for them to change to the new position and rotation.

This is a unique case. In the laser gun of the example, the laser (red beam) is actually geometry: is a cylinder that changes its length according to the hit point of a Raycast. So the direction will always follow the direction of the weapon, regardless of where you are pointing at. You could adjust this by manually changing the grab rotation for XS (mobile and PC players) in the properties panel, or by overwriting the rotations with scripting, as soon as the object is grabbed.

This is different than using a projectile launcher; with the launcher gizmo you can use the tiny white directional arrow to point towards the center of the screen.