Recommendations for suspension mods on a new truck

I am starting to suspect that the design of the truck suspension determines whether airbags help or not. As I stated a couple of times, even at low pressure the airbags add sway. If I raised the pressure into the 30-50 pound range, I could correct the level to preload but the sway became excessive and unsafe. I had a 2010 Dodge 2500 CTD crew cab carrying close to 4000 pounds. It was 2000 pounds over the GVWR.