I have a heavy old truck and usual drag my trailer, about 2500 pounds, behind it. I usually am at 12-15 psi. Truck and trailer. This last trip Tex68w with his big dodge and camper in the bed l, think he started at 25 and had no problems. Sure he will chime in and correct me on pressure if I’m wrong.
But I will say that I have been down there with other folks with totally stock 4x4 trucks and street tiresnever air down. They never have had trouble even when sand gets soft. The more aggressive tires dig more so more they tend to sink in the sand. Watch the tides and you will be fine 99% of time. I am bad at explanations. HaHa.