Any tire dealer wants to sell you the tires he carries so naturally when we ask them their brands are the best tire.
Not knowing the current tires size and load range or your trailers wheels width and load and pressure capacity were guessing. Comments like move to a E tire or go with a 16" LT E tire or a ST E or D may not be a wise choice for your smaller trailer.
Tire experts and most ST tire manufactures and folks that have pulled trailers for many years tell us to use max pressures in the tire.
Your trailer weighs 6800 lbs - 800 lb hitch weight = 6000 lbs on the tires. Now divide by four = 1500 lbs per tire minimum requirement. Tire experts and experienced RV owners also know a 10-15 percent reserve capacity is a better idea.
Now you need a tire with 1700-1900 lbs range. The tires width and pressure need to match your trailers wheels.