TBH, those tests are mostly marketing failures. EV trucks aren't really good at hauling trailers over large distances, as the aerodynamics produce a massive impact on range.

Multiple tests have shown this by showing 50% or more range reduction from pulling lightweight, non-aerodynamic loads.

The marketing failure is that the companies have allowed consumers to incorrectly extrapolate from this to thinking that heavy loads in the bed have the same issue. They actually don't as weight is a minimal impact on range.

Unfortunately, every thread about carrying sheetrock, rocks, mulch, etc shows how misinformed the average consumer has become in this space. It has to be a significant impact on sales, given that in the US these are the only heavy loads carried by >50% of the half ton pickups sold here.

Yep, so many people think hauling weight kills your gas mileage, but it doesn't really have that big of an effect unless you are hauling a massive load through stop and go traffic while in a hurry. The vast majority of people do most of their hauling of things down the highway, not through the middle of cities, and 90% of the losses from hauling load is just wind resistance against the poorly aerodynamic trailer which is a lot while at highway speeds. If someone is traveling down the highway at 70 MPH in their SUV with 1500 lbs in the back hatch, the only extra fuel it takes over the same SUV being empty is a tiny amount of extra friction in the tires that comes out to a fraction of a MPG.