I have a '13 Ram 1500, 5.7. First set of tire was Cooper AT3 D rating. Loved them rode nice incredible wear. Dealer told me no longer available.
2nd set Cooper AT 3 E rating. Great tire quiet,good on wet mud and gravel. Snow so-so Most decidedly a much stiffer ride.
My driving is much the same as yours, lots of dirt and gravel roads,soft mud several inches deep and soft field driving.
I have nothing else to compare to though. The GY wranglers that were issued with the truck sucked all the way around!