From what I see on the market, any new dually can carry any TC even Host Mammoth.
So the question remaining is gas v/s diesel or 3.5 v/s 4.1 differential.
New generation engines are beast and my 2017 Powerstroke with 3.55 differential hauls 5, 6 or even 10,000 lb on all freeway grades on overdrive.
Meaning I wish I had <3 differential for empty driving and then use transmission lower gears for heavy towing.
No experience with modern gas engines, but I think it will be similar rate.
DPF and DEF, who clicked in last years are still scary to uneducated buyers as the first years had baby teeth, but last year improved reliability, while scanners manufacturers flood the market with scanners who can monitor soot % and DPF regeneration status.
Just like with 6l Powerstrokes, the poor heat exchangers cost several engines blow ups till scanners come to the market and allow drivers to monitor engine status.