head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Mind & Math
A colonial-era RTS adding home-city card shipments to classic Age economy play.

Optimization · Mind & Math
An RTS where Greek, Norse, and Egyptian pantheons lend myth units and god powers to war.
Age of Empires III leans Optimization (Mind & Math); Age of Mythology leans Optimization (Mind & Math).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Age of Empires III
Unit micro and raid defense
Age of Mythology
Standard RTS micro demands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Age of Empires III
Human deck and timing reads in ranked
Age of Mythology
Human opponents and god-power timing bluffs
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Age of Empires III
Map spawns and shipment ordering unknowns
Age of Mythology
Fog of war and random maps
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Age of Empires III
Home-city decks are a build-crafting layer
Age of Mythology
God choices and favor economy reward planning
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.