Its the short travel of the airbags giving you the bad ride, not the pressure. I had a single-bellow style airbag (bigger diameter than my current ones) that only have ~5" of total up and down travel. It was great on the highway, but terrible off -highway and even speed-bumps. I switched to a smaller but much taller airbag, which has 11" of travel. So much better! It rides better than stock, because axle travel isn't artificially limited, but it still keeps it off the stiff overload leafs.
But X2 on the leveling kit. Those don't below on a tow vehicle. Saggy butt syndrome on a big diesel just looks silly.