From what I could find, there are two options available.

1. There may exist an option in the nvidia / AMD control panel to improve AA. Simply create a profile for that game with the desired settings.

2. You could use an ENB injector. I don't see any rules stating that it will invalidate your account, but many MMORPGs allow this, whether FF14 does or does not I'm not sure but many players on YouTube use injectors.