what is the creature growth rate for the computer?

The AI's growth rate is exactly the same as a human player's; the only cheat the AI has is that it can build structures even when it doesn't have enough resources. But in any case, on week 29, the maximum number of Titans that can be produced from a single city without the Tear of Ascha is 58. With the Tear, it's more, of course, but still nowhere near 400. So, in this case, it's about the map.