Is your in-game text corrupted, scrambled, or otherwise unreadable? This issue appears to happen to Civilization VI Mac users when their Steam Overlay is enabled.
Disabling your Steam Overlay should resolve this issue. To disable your overlay, follow these steps:
Open the Steam client and navigate to the Steam > Settings/Preferences > In-game tab. Uncheck the box next to Enable the Steam Overlay while in-game.
If the issue still occurs after trying the above, please open a support ticket with us for further assistance.