You're halfway there to maximizing the efficiency of your
fridge. Unless you have already done so, add an exhaust fan at the top vent of your exterior
fridge panels. The more air you can pull out of that box, the better. Like all fridge work, an RV evap unit works the best when not full of it's own heat from the burner / heater element as it circulates thru the lines in back of the fridge.
Get fancy and install a thermostat set at about 90° so the fan doesn't run all the time, only when needed. You can get fancy kits like this guy's vid, or you can re-purpose cooling fans from scrapped computers, buy a preset thermostat and patch it all together if you're more mechanically inclined.