Hey, I started having this exact same issue & error the moment I updated my Nvidia graphics driver to version 546.33, which was released on December 12. Unchecking the "Enable G-SYNC, G-SYNC Compatible" in my Nvidia Control Panel allowed FFXIV to actually start up / not be stuck at 5 fps / not error out.


Obviously, this isn't the greatest solution. Uninstalling my Nvidia graphics driver and downgrading it back to version 546.29 allowed me to play with G-SYNC again.

Hopefully this helps.