Thank you for the reply AidenElenor.

Since 720p is a much smaller resolution than 1800p (almost 6 times as many pixels), it would make sense that the windowed mode would be this small. Also, be aware that the launcher in the first image is going to have different attributes from the game itself.

As for the text/font size, find the 'Higher Resolution UI Settings' right under the resolution settings and select a higher resolution option.

Have you tried using borderless fullscreen mode or using a higher resolution like 1080p?

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!