I bought a 2022 F-350 7.3 4.30 Lariat last year, with plans to pull a similar 5th wheel in the future. Honestly it rides better than my 02 1500 did. The rear springs I think are the same until you get to the overload leaf.
My truck has 4204lbs of payload, and rated to tow 20k. I figured a little extra capacity is a good thing, I hate to have to push it to the limits.
It was less than a $1000 to go to the 350, and I have no regrets. My wife loves taking it on road trips even though it gets less than half the fuel milage of her Honda.
I don't think you will notice the ride difference not towing, get the 350.
