It's not too late, aren't you still taking 4K shots using DSR?
DSR sucks. It forces a gaussian blur filter which makes everything at least a bit blurry, even with "Smoothness" set to 0%. The best solution for a pure, clean supersampled image (it's "downsampling" in this case, but in practice it's the exact same thing) is to create the desired internal resolutions yourself with "custom resolutions" (such as 1.5x the resolution on each axis for effectively 2.25x SSAA or 2x on each axis for 4x SSAA) and use them instead of DSR.
I see no reason to ever use DSR. SSAA by using a custom resolution + NVCP FXAA (or Reshade's/SweetFX's SMAA in case you think FXAA is too blurry or doesn't clean up edges properly in a certain game) is always the way to go for me, that way the image is as clean as it gets (save for games which have a good TAA implementation or something similar, like Crysis 2) and it'll be compatible with practically any game since you're just running them in a larger resolution and then cramming it on your screen.