Would it be possible to disengage or disable the front wheel drive on the LX450? Purpose: easier steering, gas mileage and tire wear.
Anything is possible if you have sufficient cash reserves and a good enough mechanic.
That said, don’t do this.
You might gain a little gas mileage, but not enough to make it worth it.
Make sure the steering is doing what it should. It may be malfunctioning.
The four wheel drive is not much of a penalty on your vehicle. Tops 2MPG but usually only 1MPG. Hardly worth it.
If the steering is hard there is something wrong with your vehicle. I have owned 3 AWD vehicles and the steering difference is not different. Also tire wear does not increase with AWD again unless something is wrong.
On two sets of high perfomance tires I got 50k miles out them on two different AWD Subaru’s.