So, big lift, big tires, sticking out from the body... check.
Complaint sounds like big tires have too much leverage over the OE steering linkage.
Do you have any steering dampers? Should have a single with 33's, I suggest dual with 35"s on a street vehicle.
Alignment in spec? What is the actual caster? How about adding a half degree more? Caster doesnt wear tires, but it will increase feel and steering wheel returnability.
What is the camber? My experience says wide tires sticking out from the body, and the scrub radius, wears outer edges fast. I'd run camber at 0° to -0.25°
FYI: not enough caster will make the truck wiggle and wander driving down the road
I've always been told that steering dampers just hide problems and a good condition system doesn't need them. Is that different on these GM ifs systems?