My 2018 24 ft Ford E450 rear rides hard empty because of the 4000# payload. As you load it for a trip the ride gets better the more weight you carry .
All loaded for a trip with full water (50 gals) I sit about 12,500 with a 14,500 gvwr. I do not run my E tires at 80#, 70# works better for me.
I also added new shocks with Koni FSD in the rear and Bils in the front.
Either I'm getting used to it or its not bad, but I like driving it now.
My 1500 max tow pack Silverado hitched to a 6k TT rode smoother but you cant compare the two vehicles for ride quality.
My 350 SRW GM with a 4000# truck camper rode more like my class c .
Why not rent a class c in the size you would like and see how you like it ?