In case anyone is not familiar with these games, you are building a base, the map begins unexplored and is populated by monsters which will attack you in waves, so it is a sort of inherently player-vs-environment, very asymmetrical game.
Because the enemies are basically expendable and your units aren’t, your units should… try not to sacrifice themselves so much. They should avoid the fog-of-war areas unless explicitly instructed to go there. Melee units should flee when injured. Ranged units should stay out of melee range. Total War unit AI (where ranged units typically skirmish by default) might be a better starting point than Age of Empires style unit AI.
Although, it is a niche within a niche, so I guess I’ll take what I can get, haha.