Go through the cooling system methodically. My 98 truck had a couple of tiny leaks, and the radiator started getting bad in Spring. I finally got to it, replaced the radiator, balancer(couldn't do the WP(broke a bolt and wasn't ready to fight others), all six coolant hoses, and thermostat. The cap was already new, but now I see regular temps of 172 or less. In high heat of 90's, max was about 190 all day. Now with days in the 50's to mid 60's, my temps show under 150 most of the time, highs still at some time hit 175ish. I have the old Scan Gauge to monitor it constantly, it shows the highs for the current trip, the day, yesterday, and the tank run. I look at it often during my work day, I love seeing lower temps than 200-220 like many people report. The T'stat is a Robert Shaw 180, it's likely opening a little early, which I love.
Cooler is better for everything as long as the engine tune keeps it in closed loop. These Explorers have wonderful cooling systems, huge radiator front areas. Without a T'stat, temps would be about 50-75* over ambient.
