Seen above, there are a total of nine difficulties in Civilization VI. You are able to choose whichever you prefer, although this selection can't be changed once you've started a game.
The default difficulty is Chieftain, which is considered "Easy". This is the introductory difficulty that is best suited for new players who don't want to deal with major frustration.
There are many difficulties harder than Settler, including Deity. These are options for players who have a strong understanding of the game and its strategy elements.

Embark on an inspiring mission of human connection beyond the UCA. Sam — with companions by his side — sets out on a new journey to save humanity from extinction. Join them as they traverse a world beset by otherworldly enemies, obstacles and a haunting question: should we have connected?