As I have found out, do the math yourself for the vehicle you are looking at. Not knowing age or brand, most 5th wheels are heavy on the hitch. This counts toward your max payload of the truck, add to that the hitch mounted in the bed. Anything in the truck ( passengers are 300 lbs - just don’t tell the wife) . Just that puts most 5 th wheels over on 1/2 trucks.
I have a 28’ travel trailer, that when we bought as “newbs” the sales people and the the truck numbers from Dodge were good. Which is true on paper if your on flat ground, the is no wind, the wife is bringing a second vehicle with all supplies and you have 4 miles to stop
A little exaggeration. The fuel economy does go out the window.
Long story short do some reading and do the math, don’t just run with the numbers you see on TV or ads.