Helps to test. Drive a loop of 100-200 miles solo, approximating the TV weight while towing. Do the same loop with the trailer in tow. Or mark a course leaving town with fill ups at either end that it can be replicated in a solo trip
Solo, empty, is pretty much useless as a control. . TV needs to be loaded as if for a trip. That's the invisible number in these discussions. .
Towing is going to be a forty percent penalty from solo empty pretty much at a minimum. It'll trend towards fifty percent with a box TT. It can trend down from forty with an aero trailer.
From solo, loaded, the percent decline will be a little less, but the load on the drivetrain will be more obvious compared to empty. It's a good exercise in learning best strategy for how to accelerate and brake for when towing.