Can't use fullscreen with sub native resolution

[Torisutan]

As the title says, i have a 4k screen with 175% Scaling.
Latest version of the engine (3.471).
I can't use fullscreen with a sub native resolution.
rs_fullscreen seems not to be available anymore.
Old versions, like the one used in goldensphere work in fullscreen with 1440p for example.
As do Advanced XRay, IXRay and OpenXRay.
Example pictures:
1440p
4k

[xrSimpAI]

OGSR received native DXGI Flip Model support this year, which is great, as full-screen is a very old and problematic feature.
But for everything to work perfectly, the game window and desktop resolution must match.

https://learn.microsoft.com/en-us/windows/win32/direct3ddxgi/for-best-performance--use-dxgi-flip-model

for use fullscreen with a sub native resolution we will need to add upscaling, we will do it next year