Heck yeah, air bags are needed. I have 'em on my dually and they help the ride a lot. I can adjust via remote, on the fly.
But they don't do anything to assist with payload or towing.
Go look at your yellow door jamb sticker. It says Cargo Carrying Capacity. I'd bet yours is around 2,500, give or take. Since I bet your pin weight is 3,500 plus or minus.........you are over payload before you even count fuel, passengers, 5th wheel hitch, or cargo in truck.
"Next to prayer, fishing is the most personal relationship of man" Herbert Hoover
"American by Birth, Southern by the Grace of God"Lewis Grizzard
2016 GMC Denali 3500Dually--2017 CC 36CKTS