What do you mean "one player games"? Do you mean a "single player" game (as opposed to Multiplayer) with the default number of AI civs for a given map size (e.g., 8 civs, including you, on a standard map)?
I'm not familiar with those mods, but I would guess that they must be the source of the issue, because there's no setting in the base game to eliminate city-states.
EDIT: Just googled "master balance" and got this site:
https://civ6mods.com/2016/11/master-balance-9-3-especially-suitable-multiplayer-games/ One of the settings it says it provides is "City States: Open / Close". Perhaps that mod allows you to omit City States?