My Monitor connected to the Nvidia card does not always power off. Sometimes It remains on (green LED and backlight on , sometimes it turns off. (LED yellow)
I have not found a logic behind these behaviors. How can I debug further apart from Xorg.0.log ?

cat /etc/X11/xorg.conf.d/*

Section "ServerFlags"
    Option "BlankTime"   "2"
    Option "StandbyTime" "3"
    Option "SuspendTime" "5"
    Option "OffTime"     "10"
EndSection
Section "OutputClass"
    Identifier "nvidia-primary"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "PrimaryGPU" "true"
    Option "HardDPMS" "true"
EndSection

cat /etc/X11/Xsession.d/45custom-xrandr-setting.sh

#!/bin/sh
#
xrandr --setprovideroutputsource modesetting NVIDIA-0 && xrandr --auto
sleep 3

xrandr --output DP-0 --off --output DP-1 --off --output DP-2 --off --output DP-3 --off --output DP-4 --off --output DP-5 --off --output DP-6 --off --output DP-7 --mode 1440x900 --pos 1920x0 --rotate normal --output HDMI-1-1 --mode 1920x1080 --pos 0x0 --rotate normal --output DP-1-1 --off --output HDMI-1-2 --off --output DP-1-2 --off --output HDMI-1-3 --off

when logging out, both monitors go into power standby, LED is yellow
Nvidia Quadro P2000 connected Monitor is first in standby.

It looks like some user application is keeping NVidia from entering standby. On the net there are electron apps mentioned from doing things. I have slack and  signal sometimes running . leftovers or settings goofed from these programs  ? also chromium has a similar mention.

With above programs not used after login , both monitors go in standby after 3 minutes.