Civilization VI Resolution on Mac Retina Display

It does not look like this is currently possible. From the Aspyr support page here:

Q: Why aren’t retina display resolutions available in the Graphics Options?

A: Retina resolution support is not yet available for Civilization VI but we're looking into updating the game to add them. Double check that you have your System Preferences/Displays option is set to More Space to enable higher resolutions in game.

I tried manually setting the resolution in ~/Library/Application Support/Sid Meier's Civilization VI/AppOptions.txt, but it gets overwritten the next time you launch the game. Even making the file read-only (to prevent the overwrite) doesn't seem to have any effect on the resolution. This seems to be hard-coded into the game, so for now, unfortunately, we'll have to wait for support for higher resolutions.

Civ VI does not understand or detect retina displays. However, by modifying your display resolution you can fix it. For instance, my MBP's physical is 2880x1800. The default display resolution is 1440x900 retina. By setting it to 2880x1800 non-retina, I was able to get Civ VI to detect the full resolution. Doing this requires third-party software, such as EasyRes (free on the App Store), SwitchResX4 (paid with free trial) or other similar software. Once you launch Civ VI in the new resolution configuration, select the correct resolution and change UI upscaling till the UI is the correct size.