Interesting - first time I have seen the frontal square foot limitations for towing. With a 40 square foot limitation max, figuring a 7 foot wide trailer, if it is 6 foot tall, you have exceeded the capacity. In the travel trailer world, I think you might be able to haul a tear drop or a popup.
I did check, the U-Haul 6x12 trailer has a cross section of about 36 square feet, so okay there with the max setup. With the base setup, you are limited to the smallest U-Haul box trailer.
One of the limitations I always had with my 2009 Wrangler was the 25 sq ft limitation.
2020 Chevy Silverado 1500
Forest River Wildwood XLite 263BHXL