Idk bout AoE but Civilization is far from essentialist. In Civilization all nations have 1 or 2 bonuses but other than that they can do anything that other nations do. It can't really be classified as essentially given that 99% of gameplay is interchangeable. Memes such as Ghandi launching nukes shows that players know it's a silly game.
Agreed, if anything Civilization will spawn each civilization near terrain that benefits its unique bonuses, in other words, you could interpret the bonuses arising from people adapting to the local environment. Civ infact, has a crude historical materialist outlook. The fact that people might interpret the game as essentializing human civilizations is more caused by the dominance of idealism in popular culture.
Actually no, Civ is kinda materialistic despite minor bonuses civs get, the success of a Civ is 90% based on external/material factors
An essentialist game is actually EU4
if I remember correctly it used to be clowned on but the existence of "Barbarians" in Civ (although possibly recently removed? I stopped playing after 5) is pretty essentialist. a group of people who fundamentally, cannot be civilized, even though they operate like a civilization, in some games outright equivocated with wolves.
I don't know what civ you played but in VI they form city-states after awhile