It is almost as if it was fundamentally designed to discourage good password management habits in the first place to sell their proprietary 2fa token instead of allowing you to use your own TOTP.
If you want Auto Fill in KeePassXC to work in the FFXIV Launcher, make sure Remember ID is turned off and use the following Sequence:
{TAB}{PASSWORD}{ENTER}{USERNAME}{ENTER}
The window title is FFXIVLauncher.
This only works if you don't use a 2fa token, and takes advantage of a weird quirk where pressing Enter on the Password field when the Username field is empty places the cursor focus on the Username field.
Double fucking whammy: The launcher overrides the use of Ctrl+A and Ctrl+Z in the credential fields?
Why?
SquareEnix, it's fucking 2019.