That’s a horrible way to do since it will kill FPS. I always advice to keep the render resolution at 100% at all times. And have your resolution itself to match with your screen native resolution.
If you have 4K monitor, render at 3840x2160p at 100% scaling.
If you have a 1440p monitor, render at 2560x1440 at 100% scaling.
If you have 1080p monitor, render at 1980x1080 at 100% scaling.
Overscaling the resolution seems like a useless thing to do, because your GPU will get overworked by pushing more pixels, but you end up not seeing them since the extra pixels your GPU is generated is being scaled down and averaged into a single pixel anyway.
An analogy would be if you have 1080p resolution rendering at 200%, then you’re practically having the GPU to render at 4x the resolution, 2x horizontally, and 2x vertically. That means, for every 4 pixels the GPU is rendering, 4 of them will be averaged into 1 pixel to be displayed on the screen. So your GPU is working 4x the effort only for you to see 1/4 of what it’s generating.
Same goes the other way, you can have the game renders at 4K resolution at 50% scaling. Which means the GPU is rendering 1 pixel, and your monitor has to average that 1 pixel and estimating what the other 3 missing pixel would be. Which will give you blurry graphics.
So keep everything at 100% scaling, and just use the native resolution that your monitor has. And optimise the setting in other aspects, like volumetric clouds, special effects, object details, etc.
You can oversample the resolution if your GPU allows it of course. But to be honest, 100% 4K resolution is still better than 200% 1080p. Because at 4K, you can see all the pixels, but at 1080p, you’re missing 3/4 of the pixels that your GPU renders even if you’re getting the same performance either way.