How do I launch Dead By Daylight in exclusive Fullscreen mode?

As in for whatever reason, my game decides that "Fullscreen" actually means "Borderless Windowed", which tanks the in-game performance considerably.

How do I launch Dead By Daylight in exclusive Fullscreen mode? The PC Gaming wiki for optimizations doesn't list any sort of way to do so, but I see the term being used by others for optimization purposes.

This seems to work - copied and edited slightly from this Reddit page:

Go to C:\Users\YOURUSERNAME\AppData\Local\DeadByDaylight\Saved\Config\WindowsNoEditor
Open the file GameUserSettings.ini with Notepad.
Look for the following entries and change the value to 0:

FullscreenMode=0
LastConfirmedFullscreenMode=0
PreferredFullscreenMode=0

To change the resolution, edit these settings as you wish:

ResolutionSizeX=1920
ResolutionSizeY=1080
LastUserConfirmedResolutionSizeX=1920
LastUserConfirmedResolutionSizeY=1080

Important, you need to add -fullscreen parameter to the launch options in Steam. (Right-click on the Dead by Daylight, and go to 'Properties', then 'Launch options').