The preparation required:
https://www.nexusmods.com/readyornot/mods/4238?tab=files 
【Lumen Toggle (Global Illumination and Reflections) (Home Invasion)】Uploaded by Unselles
UUU_v523 ( Universal Unreal Engine 5 Unlocker ) By OtisInf
Engine.ini
TQNF.preset
Ready Or Not Game File
- (Make sure your Ready Or Not does not have any visual files installed, such as removing FOG and post-processing effects.)
- (Lumen works in multiplayer mode and with long sleeves or outerwear.)
- (You must read the Q&A.)
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NEW Q&A
Q: Where do I find UUU_v523?
A: please search for relevant content on the Internet and download it
UUU stands for "Universal Unreal Engine 5.x Unlocker"
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Install Lumen
Lumen is the default graphics settings for Lumen.
Lumen HIGH Preset is a higher setting for Lumen.
Choose the file you prefer and install it in F:\SteamLibrary\steamapps\common\Ready Or Not\ReadyOrNot\Content\Paks
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Install UUU_v523
Extract it to a folder of your choice.
Open to UUU_v523\PostProcessPresets
Copy TQNF.preset to the PostProcessPresets folder.
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Install Engine.ini
Find your C:\Users\(Your Computer Name)\AppData\Local\ReadyOrNot\Saved\Config\Windows.
Replace the Engine.ini in the Windows folder with the new Engine.ini (be sure to back up your original Engine.ini).
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Enter the game
Open your ReadyOrNot
Set all in-game graphics settings to maximum. For post-processing, you can set it to high or maximum (maximum settings are recommended to experience Lumen with scenes receiving more lighting).
Open the IGCSClient.exe in UUU_v523
Find the "Game process and DLL selection" under General, then select the running ReadyOrNot for "Game process to inject into"
Find the "Game process and DLL selection" under General, then select UniversalUE5Unlocker.dll located in the UUU_v523 folder for "DLL to inject"
Find the "Game process and DLL selection" under General, then click "Inject DLL" to inject the DLL into ReadyOrNot.
Find "Post-processing" under General, then click on TQNF in the "Presets" on the right (if there is no response, go back to the game, then switch to UUU_v523 and recheck TQNF).
Enter the police station locker room, find the watch, scroll down with your mouse, find Lumen, and select it.
Enjoy! Have fun!
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Q&A Questions & Answers
Q: What should I do if it’s not working?
A: 1. Make sure your installation directory is correct.
2. Ensure you have not installed any other visual files.
3. Make sure you have selected Lumen in the locker room watch.
4. When UUU is running, find the "Dynamic global illumination method" under Post-processing's "Global Illumination." You will see four options:
None  
Lumen  
Screenspace (low cost, limited)  
Raytraced (Deprecated)
You can switch to any of the other three options, then switch back to Lumen, and it will start working again.
Q: Why isn’t long sleeves working?  
A: Refer to the third answer above.
Q: Does it work in multiplayer mode?  
A: It works and performs well (if any issues occur, refer to the third answer above).
Q: I want the FOG effect, what should I do?  
A: Find your C:\Users\(Your Computer Name)\AppData\Local\ReadyOrNot\Saved\Config\Windows and change the Engine.ini setting from r.fog=0 to r.fog=1
Q: Is it compatible with ReShade?  
A: Yes, it is compatible and works very well. It can provide you with more realistic visuals.
Q: How can I sponsor or follow the Lumen mod creator?  
A: Visit Unselles' NexusMods profile page at https://next.nexusmods.com/profile/Unselles?gameId=4205.
Q: Are you the mod creator?  
A: I am not the mod creator. Without Unselles' Lumen Toggle, we wouldn't have the current visuals. All the credit goes to Unselles. I’m just trying to fix Lumen and make it better.
Q: My Lumen shadow is not working or abnormal
A: Try starting with DX12
Q: The TQNF Presets in my presets don't work
A: Switch your screen to in-game, then switch back to UUU again and re-check TQNF in Presets (no need to restart the game or UUU)
If successful, you will see a noticeable difference in picture lighting.
Q: IGCSClient.exe in my UUU cannot be used
A: Delete 111 in IGCSClient.exe 111 and make sure it becomes an exe program
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Lumen Toggle By Unselles
https://next.nexusmods.com/profile/Unselles?gameId=4205
https://www.nexusmods.com/readyornot/mods/4238?tab=files
Lumen Fix By TQNF
https://space.bilibili.com/320879998?spm_id_from=333.1007.0.0
Lumen Fix Test By 为什么叫小K & TQNF  
https://space.bilibili.com/106771946?spm_id_from=333.337.0.0
https://space.bilibili.com/320879998?spm_id_from=333.1007.0.0
Lumen Fix TAA By _Ap0k4lyps_
UUU_v523 ( Universal Unreal Engine 5 Unlocker ) By OtisInf