Borderless-Gaming VS dxvk-async

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

Right now im using this https://github.com/Sporif/dxvk-async with dxvk.enableAsync=true, it works but i got transparent assets 1-2s before it load completely, is that normal?

You can also manually install it yourself, check the DXVK_ASYNC Github page for the instructions. Maybe try to use an older version of Proton GE if you're unsure.

I also tested out Unity on my system and got the same results as you to which DXVK gplasync or the older DXVK-Async "band-aid" fixed it. Really, that's the only thing that does address issues with DX11

DXVK Async: This is a file that converts the game from DirectX9 to Vulkan, this helps alleviate issues with stuttering and massive frame drops. This version has async which renders shaders faster so it has less stuttering than regular DXVK.

Try downloading this - https://github.com/Sporif/dxvk-async

Download dxvk async 2.0 here : https://github.com/Sporif/dxvk-async/releases/tag/2.0. then open it and go inside the x32 folder and copy d3d9.dll and dxgi.dll then paste inside C:\Steam\steamapps\common\Mafia II\pc.

Jedi Fallen Order (Epic setting) was a little quirky with stuttering, but was rectified when I used DXVK_ASYNC and entered DXVK_ASYNC =1 in Settings > About > Advanced System Settings > Advanced Tab > Environment Variables > System Variables > New > Variable Name = DXVK_ASYNC, Variable Value = 1, and that reduces the issues quite a bit. Vanilla DXVK 2.1 didn't work out as well for me, but I might try it again as 2.2 came out recently

J'ai trouvé quelque chose appelé dxvk async. https://github.com/sporif/dxvk-async