My settings:
Standard mode
74 contrast
50 saturation
color temp user mode: R 100, G 90, B 89

I have an nvidia card and i adjusted the color settings through nvidia control panel, because I wasn't happy with the results i was getting through the calibration on my monitor. I am sure there is an alternative for other video cards

It had more options such as controlling the vibrance and the gamma rather than just the color temperature, brightness and contrast.

I have a BenQ 2420z, not that it really matters

https://pcmonitors.info/reviews/asus-vg248qe/

I just looked at color settings from various reviews of the monitor on Newegg. This monitor is really nice with neutral colors.

the higher refresh rate you go, the more washed out colors get

Don't expect any miracles, especially the gamma is a nightmare.

This is what I mean with "shit colours". I'm not warning everyone for fun, the colours on 120/144Hz TN panels are really bad. That's the reason why I can't understand when someone knows they won't use lightboost because of the worse colours and reduced brightness (or even worse the "input lag") yet still gets a LB monitor (=TN panel), instead of a >100Hz IPS or at least VA panel, so they can bitch about the colours anyway. I'm hoping that's not the case here.

If you didn't know about the colours: Sucks, but that's why you do your research before buying anything.
I know it's not helping but without a colorimeter you're out of luck.
If you're fine with the settings they used and no lightboost (why were you getting theVG248QE again?) the ICC profile from pcmonitors is your best bet. Obviously it won't be perfect, it was created for a different monitor after all, but it'll definitely be better than what you're seeing now.

I was going to make a thread on this the other day after I switched from lightboost to 144 hz but I figured out my problem. this probably won't be your problem but for some reason when I switched from lightboost > 144 hz, under the NVIDIA Control Panel, my color depth changed to Medium (16-bit) when it should be Highest (32-bit). make sure you have it at highest (32-bit). I've experimented with numerous settings recommended by people on different sites and forums but I've found the settings below to suit my moniter and preference the best.

settings:

theatre mode
brightness: 27
contrast: 43
saturation: 54
color temp user mode: R 100, G 95, B 93
sharpness: 40
trace free: 60
ASCR: ON (makes your screen brighter, preference really but I really like it on for gaming)

wow this is awesome. I used the calibrated color profile and je-sus everything is so much better.

My settings are

Standard mode
Brightness 35
Contrast 80
Saturation 50 (Although I use Digital Vibrance at 100)
User Mode Red 96 / Green 94 / Blue 88

I also use a color profile based around Nvidia Graphics cards or something, will post link if I can find it for those who care.

Hey, sorry for bringing up a dead thread but I found a setting that people should try out if they have problems with PWM. Setting the monitor brightness to 100 stops the PWM, but the white luminance on a default splendid destroys my eyes.

Splendid: Game Mode
Brightness: 100
Contrast: 100
Color Temp: R - 75 G - 75 B- 75
Everything else at the default game splendid settings

How have you not gone blind?