Basically the game is bugged and the Render Resolution at 100% is not 100%, but rather you need 200% render resolution to get 100% native resolution, this guide is basically how and where to change that option.

Also as an added bonus, if you notice graininess, that is the denoiser for the "Reflections" setting which uses raytracing. If this also bugs you, disable that too, you'll still get screen based reflections.

From the Main Menu, just select "Config":


If in game already, go to the Pause Screen > "System > Config":



Go to "Graphics Settings > Rendering Scale" and change this to "200%", due to the bugged render scale in this game, this will give you the equivalent of native resolution.



Also if you notice your image is grainy or you lose a lot of performance, disable "Reflections", they are raytraced and add denoiser grain + FPS loss. You will still get screen space reflections with this setting turned off!

Ugly and Compressed:

Fixed and Crispy: