Greetings, Curators!
Codex Lost doesn't let the player individually change various graphical options, with all of them instead being part of the "Post Processing" setting.
Luckily, since it is an Unreal Engine game, we can modify those settings from outside of the game.
Following this guide will disable motion blur, depth of field, chromatic aberration, lens flare, and vignette (plus some small optimisations).

Go to the following file directory on your PC:
Appdata > Local > Codex_Lost > Saved > Config > WindowsNoEditor
Open the Engine.ini file and add the following text to the bottom of the text contained within, with an empty line between the existing text and the new text:

[SystemSettings]
r.Tonemapper.Quality=1
r.TonemapperFilm=1
r.MotionBlurQuality=0
r.MotionBlur.Amount=0
r.MotionBlurSeparable=0
r.DefaultFeature.MotionBlur=0
r.MotionBlur.Max=0
r.FastBlurThreshold=0
r.SceneColorFringe.Max=0
r.SceneColorFringeQuality=0
r.DepthOfFieldQuality=0
r.DepthOfField.FarBlur=0
r.LensFlareQuality=0
r.MaxAnisotropy=16
r.SceneColorFormat=4
r.EyeAdaptationQuality=3
r.FastVRam.EyeAdaptation=1
r.Emitter.FastPoolEnable=1
r.TemporalAA.Algorithm=1