Is there a working DPMS config for GPU with DisplayPort?

Hi There,
Using a Linux/RHEL setup and I am unable to get my monitor to sleep (it blanks but does not turn off).
Any tips?

Driver: 565.77
OS: RHEL8 with Xorg
GPU: Nvidia A4000

xset reports DPMS as enabled and I had this in my X config:

Section “Device”
Identifier “Device0”
Driver “nvidia”
VendorName “NVIDIA Corporation”
Option “CustomEDID” “DP-0:/etc/X11/DELL_U4320Q.bin”
Option “AddARGBGLXVisuals” “On”
Option “AllowEmptyInitialConfiguration” “On”
Option “PrimaryGPU” “yes”
Option “SLI” “Auto”
Option “BaseMosaic” “on”
Option “AllowSHMPixmaps” “On”
Option “Coolbits” “4”
Option “HardDPMS” “true” <================================
EndSection

Any ideas? Did I typo something?