Xfce Power Manger: Disable OSD messages?

[PeR9BbSFQ42Z7Rrs]

I'm trying to setup my display (Dell P2419H) to blank after 10 minutes. My display turns off for a second, then there are several OSD messages. Finally it goes into sleep mode instead of a blank screen because the power led is pulsating? This is wrong I guess?
There seem to be no difference between blank, sleep and the switch off setting.
Is this normal? Is there a way to disable the OSD messages? I already tried to find a setting to disable in my display's OSD menu.

Photo's:
https://imgur.com/a/RnIEXTW

[I2k4]

I've never used and don't know why the Power Manager / Display setting in the photo doesn't work. I use the following Keyboard shortcut (set to Super-Z) in order to toggle display off, mainly while listening to music or audiobooks.

sh -c 'sleep 0.3 && xset dpms force off'

Launch Keyboard / Application Shortcuts tab / Add button. Paste in the above and select the Key combination for it. For me, toggling Super-Z turns the screen off. Any mouse movement or key toggles the screen back on without affecting any other settings. Not sure if that's what you want. It's obviously a personal preference, but I disable all the automated timed settings and manually use the Log Out / Suspend or Shutdown dialogs when wanted.

[ricardogroetaers]

Photo's:

Turn off "Screen Power Management".