Jeez...... my old '03 2500 Dodge/Cummins HO NV5600 quad cab 3.73 gears 2wd short bed pulls my 11200 lb 5er ....and a 14k tandem and a 16k GN tri axle trailer with no issues....and has done so for over 300k miles now.
MFG payloads are a GVWR based payload and are not a good indicator of how much any truck can safely carry.
My gen truck has a 6000 rawr which leave it with around 3200 lbs for a payload in the bed.
The new gen 2500 Rams have 6000/6200/6500 RAWR so it makes a difference in payload in the bed such as a GN or 5th wheel or some type of bumper mounted hitch.
A 3500 SRW has a 7000 rawr and is good for around 3600-4000 lbs in the bed depending on truck selections.
I would suggest the white one.