Need better support for 3:2 lower resolutions

I purchased a Surface Book 2 last summer and have struggled to get optimal performance in FFXIV while running in windowed mode. After playing with various lower resolutions I discovered that there is no support for a custom resolution at full screen, and also no lower settings for the weird 3:2 resolutions that Microsoft decided to put on this device.

Is there a way to set the screen resolution in XIV to 3:2 outside of the baked in resolutions under graphics settings? If not, are there any plans to support the lower 3:2 resolutions?

Resolutions needed:

3240x2160 (supported only at full screen)
1920x1280
1800x1200
1728x1152
1440x960

Good afternoon and thank you for posting on the Final Fantasy XIV Technical Support Forums.

The Fullscreen option should allow you to choose any resolution usable on your desktop. You mentioned using a custom resolution, how did you go about creating a custom resolution? I ask because I tested this and was able to make one using the Nvidia Control Panel and set the game to 1920x1280 in Fullscreen.

It sounds like those other resolution options aren't native to your screen.

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

I can use custom resolutions while in Windowed mode, and set it to any of the above ones I have listed. The result is a massive FPS hit - at full screen I'm at 60+ consistently but any kind of Windowed mode with a reduced resolution kills it.

I have not tried this using the Nvidia Control Panel instead of the in-game tools, however, so I'll give that a shot.