The thing about Light Truck tires is that the same size can often come in different Load Ranges - Load Range C, Load Range D, Load Range E, etc. The higher the load range, the more weight each tire is capable of carrying.
Was I you, I'd load your Durango up exactly how I plan to travel with it, all the passengers, all the luggage you plan to carry in it, a full tank of gas and take it to a scale and get it weighed. You can find CAT scales using this web page:
https://catscale.com/cat-scale-locator/
Now, to that weight, remember that you need to add 10 to 15 percent of your fully loaded trailer weight (the Tongue Weight) plus about 50 to 100 lbs for the trailer hitch.
Now that you have the ACTUAL, Gross Vehicle Weight that you need to deal with, go to your current tire manufacturer's web site and find exactly how much weight your current tires are capable of carrying. Since you have an SUV, I'm gonna guess you've got Load Range C's on it now, and they
MAY turn out to be fine. Or you may decide you need to buy rear tires with a higher Load Range.