Borderless-Gaming VS FF13Fix

You can. I use it to persist settings in my app Borderless Gaming https://github.com/Codeusa/Borderless-Gaming

This and this work, but they mess up OBS recordings so I stopped using them

Yes you can do that with any ultrawide. Simplest way is to just play windowed mode with a 16:9 resolution. If you want it to be 16:9 borderless windowed in the center of the screen you can use BorderlessGaming with a "Set window size" config, though that approach can be a bit inconsistent sometimes.

I don't know if its a fix, but Try grabbing Borderless Gaming. See if you can force it into a resolution you want. I would try it myself but...

Turn off screen rotation lock and rotate the display so it's portrait. This allows us to launch the game without issue into windowed mode (it's full screen landscape that's the problem). Now rotate the screen back to landscape, game will still be running in a window. Now use Borderless Gaming (or your favorite borderless window full screen app) to make the window into full screen. https://github.com/Codeusa/Borderless-Gaming/releases/tag/9.5.6

You could try Borderless Gaming - Free version BorderlessGaming9.5.6_admin_setup.exe - July 2019: (https://github.com/Codeusa/Borderless-Gaming/releases/tag/9.5.6)

Borderless Gaming is another free alternative that doesn't do anything fancy like improving the image quality but can also do the job of making your games fullscreen: https://github.com/Codeusa/Borderless-Gaming/releases

The ports aren't perfect, but the only mod you really need is FFXIII Fix for XIII and XIII-2. Lightning Returns is fine from my memory.

I prefer using this on PC and Deck for smooth gameplay: https://github.com/rebtd7/FF13Fix/releases

If you apply FF13Fix you can make the game run pretty much perfectly at 60 FPS and nearly perfectly above 60 FPS (characters' lips desync in cutscenes unless you cap to 60).

The most important factor when it comes to getting a decent framerate on the PC version is your single core CPU performance. The GPU doesn't have a big influence. What that means for laptops goes beyond my understanding, but what I can do is recommend is the FF13 Fix. This is a fan made fix, that helps with framerate and some other minor bugs. It even allows you to exceed 60fps, but I would avoid that since the game can behave weirdly above 60.

I tried with FF13Fix but it still didn't fix the overall framerate. Oddly enough, when I tried it in Windows, it crashed all the time. With Linux / DXVK, a got a little better performance (after it compiles the shaders of course).