I ran XPS tires on my ‘95 F350 CC dually, and loved them. I doubt the tires are the problem. Before having the steering gear box replaced at about 200K miles, it was getting a little squirrelly though. It took almost constant input on the steering wheel to keep it going straight. There is an adjustment on the gear box to tighten it up a bit, but be careful playing with it. If you adjust the play out of a worn out unit, you will find that the steering wheel will no longer want to go back to the centered position on its own coming out of a turn.
With your new TC I would weigh the truck empty and with the camper loaded to see if it is unloading the front axle. You may find that it’s taking a lot of weight off the front.
:):)
