That truck has a Dana 70 rear axle. Dana rates it for 7500 pounds, even though Dodge put a lower number on it.
It’s probably a great rig.
Your camper weight expectations aren’t realistic. Listed “dry weights” are pure fantasy land.
In general, that truck should be fine with any camper in the 8 to 10 foot range.
FORGET buying any half ton. 2500s are way under-rated. The biggest weight issue with half ton trucks is the wimpy rear axle. The wheels ride on the axle shafts, with one small bearing at each end.
3/4 tons generally have “floating” axles with a hub on each end that rides on two large bearings. The axle shafts just supply the power.