On a leaf-sprung truck, movement of the body against the suspension is what is "felt" at the steering wheel with a hard, sharp crosswind (passing truck).
It isn't a problem of tire pressure.
Inflating the tire very much past the point of "equalization" (where pressure rise is minimized; at the value closest to the Load & Pressure Table) decreases handling and braking. Bad idea.
Tune the suspension.
On my 35' TT with HA hitch I did not register a passing truck until the truck bow wave hit the rear of my pickup.
Antiroll bars were the solution.
Tire pressure remained 50-FF and 70-RR per Scale values and Dodge door sticker before and after.
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