The AI is dumb. Last civ game I played is Civ beyond earth and i gave up hope on firaxis developers of being competent enough.
Lets for starter, AI don't know how to move and shoot with ranged units in same turn.
I don't know the state of AI in civ6 but I suspect its exactly the same with tiny adjustments to ai programming to take account of new civs.
Even then, in Civ5 the indonesia AI is complete blank,it doesn't know how to expand to islands to take advantage of three unique luxuries that it has access to.
I expect the same of civ7 AI to be completely braindead and I won't be buying it. After all, why pay fifty dollars for no improvement in AI whatsoever. They've had decades to make their AI more competent so I could have more entertaining wars not shooting fishes in a barrel.
So I strongly advise you to not get your hopes up. Civ games is just really just..... an mediocre building race game. Build your granary and library, etc as fast as you can and you're done.