Just some thoughts on this subject. I do believe the radiators on our 1500 Rams are a bit undersized to keep coolant temperatures high. Thats good for emissions. Not good for power. A properly sized radiator will efficiently shed engine produced heat, even in extreme conditions, so that coolant temperatures will remain at, or within one or two degrees of installed thermostat calibration.
In the days before our present super tight emissions, if one installed a 180 degree thermostat for example, coolant temperatures typically were very close to 180 degrees, as OEMs weren't as concerned with emissions as cooling efficiency. In my 2011 3500 Ram Cummins, coolant temps with the 190 degree thermostat I installed (down from the OEM 203), stayed @ 190 degrees regardless how hard I worked the truck, whether AC was on or off, or ambient temperatures. That truck had a huge radiator, as the truck was meant to work.
I installed a 170 degree thermostat in my 2012 Boss 302 Mustang, and even during very hard running on hot days, coolant temperatures sit at 170 degrees. They climb when I stop moving, but drop right back down when under way again. That car has a very large, all aluminum radiator.
I've got a 180 degree thermostat in my 2017 Ram, and coolant temps fluctuate from 185 up to 190, typically remaining between 186 and 188. My shutters are all removed, save the uppermost and lowest one.
I've not found any supplier that offers a performance radiator for our trucks. Personally think the only way to really keep coolant temps equal to installed thermostat calibrations would be to have a custom, all aluminum performance radiator fabricated, or source a radiator from a 2008 - 2012 Ram with Cummins, with all of it's attendant attaching pieces and try to install it in a 1500, but even with that, a lot of component relocation and fabrication would be necessary.
