You don't have to have a dually. I was talking about a long time ago. Now, You can easily get up to around 4500# payload in a SRW HD. But it won't be a Tremor or a ZR2. Even back in 2017 you could get a SRW with 4500# payload.
Also don't misunderstand. They all have the same engine, transmissions, ect. A ZR2 HD will pull a 16k trailer. Especially with airbags or helper springs added. But the suspension reduces its rated capacity. Which means if you are ever checked or have a wreck, ect. You will be considered overloaded. This could be a ticket, or this could be a state trooper not letting you continue on down the road. It also could be trouble with insurance if you have a wreck. Whether it's your fault or not.
Warranty could also be a problem. Not sure if you seen that dodge dually broke in half with a truck camper on it. Warranty claim refused. Dealer told him the truck would haul it. He thought it was with in spec because he was going of the cargo capacity of a base model Cummings.
If you are starting from scratch, it just makes sense to buy a combo that is with in its rated capacity.