Looking at the iKamper (Rooftop Tents - iKamper) for another vehicle and started wondering about the Niro. iKamper distinguishes between dynamic weight, the weight of the load when driving and static weight, the weight that can be supported when the vehicle is not in motion (Mounting - iKamper). The Niro EV manual lists the roof rack as supporting 220 lbs...that would be the dynamic weight, what you could carry rolling down the road. They don't list what iKamper calls the static weight (that would be my wife, myself, and some stuff in the iKamper at night). I may have to ask Kia, but my chances that someone here knows and would respond more quickly are a good bet.
Sorry to dredge up a super old thread, but I was wondering if you ever got an answer to this question.