Method for user configured brightness and contrast? (For dark games)

Hi,

Our game looks too dark on some monitors and too bright on others. I’d like to add a screen at the start of the game that lets users configure the game’s brightness and contrast to suit their monitors but the only method I’ve been able to find is by using a post processing volume in a level. Is there some engine/game setting I can use?

How would others go about doing a brightness and contrast config page?

Many thanks,
D