Anyway to stop monitor from downscaling to game resolution?

Anybody know if you can stop monitors from downscaling when you drop your game resolution? I discovered a wonderful thing when my 4k TV didn't know how to downscale to 2560x1440. The TV would would stay at 3840x2160, but the game would go to 2560x1440 and then the GPU would stretch the image to a perfect 16:9 fit. The result is gorgeous with a massive boost in FPS. My 4k monitor on the other hand downscales to 2560x1440 with the game and turns it into a blurry mess. Is there a way to stop a display from downscaling? I also have to wonder why a display downscales in the first place, if anything it should just stretch lower resolutions because as long as you maintain the same aspect ratio the image stretches to a perfect fit.

Thoughts welcome.

I was going to suggest running the game in windowed mode but that doesn't seem to be the solution you're looking for :/ Sorry I couldn't be of more help

What graphics card do you use if nvidia go to NVIDIA control panel (advanced)>Display>Adjust desktop size and position>Do not scale

I partially just forgot, NVIDIA control panel, GPU scaling, maintain aspect ratio. Thanks for the help.