It was long long struggle to get everything right but I think I finally reached good enough settings for this monitor... It really is problematic to configure it properly. I can finally say that reaching good black and whites value without destroying colors is possible. Not ideal but best from both worlds I think..
As others said before ICC Profile is essential but none good enough were proposed. Try one from herehttps://pcmonitors.info/reviews/benq-xl2420z/
It must be the 120 Hz one.
This is for VT1500 1920x1080, single strobe On, monitor set to 120Hz.
Picture Mode Standard
Blur Reduction ON Intensity 16-18 (I assume it is still safe for leds lifetime + decent amount of BR without very dim screen)
Black Equalizer 0
Color Vibrance 10 ( makes sure that Your black/whites levels are distinguishable)
Low Blue Light 0
Instant Mode On
Auto Game Mode Off
Color Temp Normal
Real problem with this monitor is choosing between horribly washed out colors but good black/white levels or vice versa. While using thees settings and ICC Profile and testing images from lagom I can say it gives correct contrast from 1 to 32, good sharpness, almost ideal 2.2 gamma (blue is a little off), all black levels and white saturations from the very first to last square. On plus note it finally stop trying to burn my eyes out
Please give it a try and say how You find those settings.