ok ... your PC (MSI GF 63) has GeForce 1650. That should be plenty for 4K. Unfortunately, there are not much info on your projector ... other than it is HD but can do 4K by flashing HD 4 times (never heard of something like that ... most i heard are TI chip that need to flash twice to get 4K).
Since it seems you are not so good with computers, I try to be as detail as possible
1) first need to figure what refresh rates your projector support at 4K. Go to NVidia Control Panel (see first attached picture).
Set output color to RGB and Dynamic Range to Full. Select 3840x2180 and see what refresh rate your projector support (you can see my TV support 60, 59, 50, 30, 29, 25, 24, 23)
2) now go to MC. [Tools]->[Options]->[Video]. Set [Display Settings automatic change mode] to off (we will let MadVR switch mode ... as I recall recently somebody had problem with MC switching)
3) In [Tools]->[Options]->[Video] click [open MadVR settings]. In MadVR settings go to [devices]->[display modes]
Copy all settings from my screenshot ... except [list all display modes MadVR may switch to] ... here you have to take refresh rate you found in Step 1 and put it behind 2160p
For example, if you found in Step 1 that 3840x2180 can only support 30Hz and 60Hz, you put "2160p30, 2160p60"
4) In MadVR settings go to [devices]->[HDR]
Copy all settings from my screenshot ... except [target nits]. Setting this value higher increase "HDR effect" ... setting this value lower makes picture look brighter. Start with 100 ... change it until you find best value for your projector.
Once you happy ... post ctrl+j screenshot so we can check if your PC can handle these settings
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