You can find your GameUserSettings.ini in
"C:\Users\*your user name*\AppData\Local\HOLE\Saved\Config\Windows"
then change first section to this

[ScalabilityGroups]
sg.ResolutionQuality=0
sg.ViewDistanceQuality=0
sg.AntiAliasingQuality=3
sg.ShadowQuality=1
sg.GlobalIlluminationQuality=0
sg.ReflectionQuality=0
sg.PostProcessQuality=3
sg.TextureQuality=0
sg.EffectsQuality=0
sg.FoliageQuality=0
sg.ShadingQuality=0
sg.LandscapeQuality=0

then create another text file name "Engine.ini" in the same folder, then paste this down

[/script/engine.renderersettings]
r.AmbientOcclusionRadiusScale=1
r.DynamicGlobalIlluminationMethod=2
r.ReflectionMethod=2
r.Shadow.Virtual.Enable=0

and save this, then right click on Engine.ini and go to properties. click "read only" then apply and ok.
(if you're lag then change the r.Shadow.Virtual.Enable=1) might work depends on your device.

*added* If you want to revert all the setting back, delete "Engine.ini" or "GameUserSettings.ini" too. when you re-opening the game it would make new GameUserSettings itself and use the default one setting that been made for this game

And there you go! Have fun with this game!
Special Thanks to my friend who optimize this game!

shout out to dev, please add graphic setting lmao

(Not me Magame but my good friend who make this optimization possible)

GameUserSettings.ini, as the name suggests, is used for basic user-defined game settings. However, it lacks access to some deeper or more advanced configurations. Certain commands only work in Engine.ini, so that file must be used instead for more advanced settings.

Regarding the term "methods", it depends on each specific command. different commands have different methods.

Here are just two examples:
r.DynamicGlobalIlluminationMethod=1
This controls the dynamic global illumination method (i.e., how dynamic lighting is calculated).

0: Off
1: Use Lumen (a system developed by Unreal Engine similar to ray tracing)
2: Use SSGI (a fake, lower-performance-cost version of ray tracing)
3: Use true Ray Tracing (e.g., RTX)
4: Use a plugin (must be provided by the developer to be usable)

r.ReflectionMethod=2
This controls the reflection rendering method.

0: Off
1: Use Lumen (Unreal Engine's ray tracing-like reflection system)
2: Use SSR (Screen Space Reflections — widely used in many games, lower performance cost while still visually pleasing)
3: Use true Ray Tracing (e.g., RTX)

Shadow virtual enable refers to enabling virtual shadow maps, a more realistic and detailed shadow system that is very performance-intensive.
However, I encountered a bug: when it’s disabled, it should theoretically improve performance, but instead, the game experiences frequent stuttering. So it's best to experiment with enabling or disabling it to see which works better on your system.