I think we are in danger of misdiagnosing the problem. Hordes of Chariot Archers are a nightmare, but we all know this so just hit the enemy before he has them running around enmass with either a Tool Rush or Cav/Camels early Bronze or get your own Chariots or Compies/Stone throwers for a late bronze showdown.
The problem isn’t Chariot Archers it’s specifically Assyrian Chariot Archers as the Tool rush is basically off the table (unless you Yamato Scout rush) due to their villis outrunning axeman, whilst with the wheel stacking they can evade cav easier. Their rapid firing bows make their CA’s the best in the game but also make them harder to Tool rush as their bows are better too and most Assyrian will build a bow or two in the transition to Bronze (guarding against scouts) .
I don’t really understand why the Upatch gave Assyrian chainmail armour as its Iron where other civs scythes start to tip the balance against them. The balance with Assyrian was that they were strongest in Bronze but then tailed off in power in Iron. In team games it was OK.