I had a 2006 2500 Cummins with a 6 speed and 3.73s. I hauled everything with that truck, including excavation equipment. When I sold my drag car, I sold the truck. A few years back, I started camping and bought a large camper. I now have a 2015 Chevy HD gasser with 4.10 gears. One of my best friends has a 2020 Ram 2500 with a 6.4 and 4.10s. Neither of those gassers will pull anywhere near as well as the '06 did. Pulling a lightweight hauler with a UTV in it, his 6.4 gets about 10mpg and isn't a fan of hills. My diesel with the drag car behind it got high teens.
I've said for years, I should have kept my '06 Cummins. Just saying.....