I recently saw a PSI/load table (40-80 PSI) for a 275/70/18 E-rated LT tire with a maximum load rating of 3,640 lbs. at 80 PSI. At the low end of the table, it listed the maximum load for this tire as 2070 lbs. when inflated to 40 PSI.
The OP said his tire load was 2,800 lbs. Interesting to note the minimum tire pressure necessary to support 2,800 lbs. while using the above 275/70/18 LT, 3,640 lb. rated tire was approx. 55 PSI. Just for the sake of discussion, if we transpose this 275/70/18 LT PSI/load table to a 4000 lb.,110 PSI rated tire it would indicate 75 PSI is necessary to support 2,800 lbs.
Am I saying the OP should use 75 PSI? No, I'm not, But, I do find the transposition interesting.
FWIW, our trailer has 2,250 lbs on each tire. We've been running 80-85 PSI in our 4,080 lb./110 PSI/G-rated tires for 8,000 miles (several times in 110-115 degree heat) with no abnormal wear or other issues noted. When we tried running 110 PSI we noticed only 70-75 percent of the tire was contacting the road surface. This increased to 80-90 percent at 80-85 PSI. Again, note this is with a relatively light load (for a 4,080 lb. tire) of 2,250 lbs.