The major difference between each of the difficulty levels are the bonuses applied to the player and AI. These were well known in Civ V, but unsurprisingly it doesn't look like there's any hard data on Civ VI yet. I've tried looking through the various foldiers and files in
\Base\Assets but haven't been able to find any hard numbers, although I know you could find that information in the equivalent config files for Civ V.
What are the modifiers applied to the AI and player at each difficulty level?