FWIW, while code requires a GFCI in many locations today including a garage and outdoors (and kitchens and bathrooms, etc.!), all EVSEs have that logic built into them. It is self resetting, though as opposed to requiring a manual reset like the receptacles.
As mentioned above, though, the most common overheating problem is either a worn out receptacle (did the plug slip easily in, or did it take some force?), or loose or corroded supply connections. You're dealing with a fairly large, continuous power draw. Any loose or corroded connection acts like a resistive heating element that generates heat. Leave it long enough, and things can get messy. Once that happens, things can short out internally in the receptacle, that has nothing to do with the EVSE (OUC) unit and would happen with anything else plugged in there.
Unless you've changed them, the typical receptacles installed in a home in the USA are about the cheapest ones available. One rated industrial (would look the same) will have bigger contacts and will last longer. The things DO wear out. When it's easy to slide the plug in, it's time to replace them. It should take some force, and hold the plug easily in place.