AI difficulty in multiplayer

My wife and I sometimes play Civ6 together, but I'm a more experienced player and so she has never won a game (unless we play in teams). I was wondering how we could balance the difficulty to give her an advantage, but also without making the AI players too weak for me.

I'm trying to understand how the difficulty level applied to the players interact with each other and to the AI. Let's say she's set to Chieftain and I'm set to Emperor. My instinct is that, between us, she'll have attack bonuses on her units. But what about the AI? If the AI is set to Emperor too, will they be strong against her too? Or only me? What about their yields? Should I set them at Prince?

We have only ever played with all players and AI set at the same level, so I'm not sure how that all interacts.