It seems many owners have the same issue. My steering wheel is also a little off centre.
It's fairly easy to adjust & I will probably ask the agent to do this when I go back to get the software update.
Basically, on all solid axle cars (like the Grenadier), the steering is performed by a Drag link attached to the front wheels.
The drag link is moved side-to-side via a steering box (and of course the steering wheel in your hands!.
The steering box is connected to the drag link by a Pitman arm and a "Sleeve".
It's the Sleeve that can be adjusted which in turn adjusts the Pitman arm position of the steering wheel relative to the position of the drag link without impacting the alignment of the front wheels.
Probably a 30 minute job but much easier if your Grenadier is on a hoist.