Please allow the game to take higher resolutions from nvidia's DSR factors

Hi. I want to use NVIDIA's DSR factor with this game to take advantage of my GPU's power since my CPU isn't from the current generation and I don't get many FPS even if I lower the graphics quality, but the game also doesn't allow using that downsampling technology. I've noticed that the game only lists resolutions up to the one I have selected in my desktop settings and no higher. Other games in borderless window mode do allow increasing the resolution above my monitor's, and DSR makes these games look great. In Marathon, these higher resolutions for downsampling only show up if the game detects that the GPU's video settings are also set to those resolutions, but sending 4K video to my 1080p monitor limits the refresh rate.
The weirdest thing is that I found that by increasing the resolution to 4K before opening the game from the desktop, then setting it to 4K in the game, and then switching the desktop back to 1080p while the game is still running, the game stays in full screen (showing on my 1080p monitor at fullscreen) but renders from 4K and does downsampling, and it looks spectacularly good... but because of the resolution change, I can only move the mouse in a quarter of the screen. Please add proper compatibility like DSR, this would make the game look much better on systems where the bottleneck is the CPU.