3/6/24 comment: I've just returned to playing the game and I will look into making this work!

WHAT IT DOES
Adds 5 new map sizes;
Mighty: for 20 players (116x72)
Massive: for 22 players (128x80)
Gigantic: for 24 players (140x86)
Colossal: for 26 players (180x94)
Monstrous: for 28 players (230x115)

KNOWN ISSUES
1. Colossal and Monstrous sized maps - WAIT for each turn to complete or you will lock the game!
2. Gigantic map may also lock up if you get to click-happy when it's not your turn, but not as often.
3. Colossal map - When you go to the civ interaction screen (first meeting or other) the graphics looked washed out, colors missing, like they're not rendering fully.  Screen still works, but it can be difficult to see what's going on.
4. the Bigger the map, the longer to generate.

The world globe spinning will stop spinning... that pretty much says you're locked up.  You can wait if you want, but I wasn't patient enough to wait more than a couple minutes.

These issues could be related to my video card (it is older *shrug*).

For reference, I have:
AMD 3.6GHz 8 core
32G Ram
Radeon 5700 Gfx card (1G on it, shared for a total of 5G)

With this, it takes about 3 minutes for a gigantic map to generate, 7-9ish minutes for the colossal, and about 15mins for the Monstrous.

You are warned!  :D

HOW TO GET IT
Select it from the 'Map Size' drop down at Game Creation.

HOW TO INSTALL IT
Open the downloaded file and drag the Mynex_LargerMapsfolder into your "Documents/My Games/Sid Meier's Civilization VI/Mods" folder.
It should auto-activate itself the next time you start the game, but you can still turn it on and off in the menu, under Additional Content.

HOW TO UNINSTALL IT
Delete the Mynex_LargerMapsfolder from there.

COMPATIBILITY
It is compatible my other mods;
http://www.nexusmods.com/civilisationvi/mods/9/?

and with Moraelin's "Daughter of..." and "Tougher City States" mods.