This comes from How to enable Night Light feature on DisplayLink devices in Windows 10.

I have a Targus docking station and luckily it used DisplayLink, the key does not exist with the Targus drivers installed so…

  1. Go to https://www.displaylink.com/downloads/windows and download the DisplayLink drivers.
  2. Install them.
  3. Start RegEdit
  4. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\DisplayLink\Core
  5. Create new String value with name EnableGammaRamp and set the data to be: true
  6. Unplug and plug your DisplayLink device
  7. Enable Night light in Windows

All your monitors should now be at the same gamma settings.