Truck is lightly loaded, doesn't pull heavy, and only sees local trips. With that knowledge, start with the easy stuff. Tire pressure. Most likely the tires are aired up to whatever the max load # is on the sidewall which is standard protocol for most people. Don't do that.
I run 20 psi in the 33 12.5 15 BFG MT's on my '79 CJ-5 on the road. 10 off. In my Jimmy I run the 35 12.5 16.5 BFG AT's at 26 psi. Which is probably a little high. I ran the old 35 14.5 Mickey Thompson's at 24 psi.
You can tune the ride based on psi and load. You can put chalk powder across the ire face and push it back and forth and see how much of the tread pattern is on the road. Adjust pressure so it scrubs evenly across the surface.
Link is for jeeps, but same idea applies:
https://txtire.com/blog/view/jeep-ti...versized-tires