Disable energy saving settings completely? HDMI signal lost (DPMS and screensaver already disabled)

On my MX Linux XFCE environment I have the problem that after a certain time without interaction after power on the HDMI signal is lost and can only be retrieved with pressing a keyboard key. I would that the HDMI signal or display never switched off. I have already deactivated DPMS and the screensaver. Apparently this is not enough. Do you have any ideas about the possible cause? I'm using a nvidia optimus card if this information is relevant. $ xset -q ... Keyboard Control: auto repeat: on key click percent: 0 LED mask: 00000000 XKB indicators: 00: Caps Lock: off 01: Num Lock: off 02: Scroll Lock: off 03: Compose: off 04: Kana: off 05: Sleep: off 06: Suspend: off 07: Mute: off 08: Misc: off 09: Mail: off 10: Charging: off 11: Shift Lock: off 12: Group 2: off 13: Mouse Keys: off auto repeat delay: 500 repeat rate: 20 auto repeating keys: 00ffffffdffffbbf fadfffefffedffff 9fffffffffffffff fff7ffffffffffff bell percent: 50 bell pitch: 400 bell duration: 100 Pointer Control: acceleration: 22/5 threshold: 4 Screen Saver: prefer blanking: yes allow exposures: yes timeout: 0 cycle: 600 Colors: default colormap: 0x22 BlackPixel: 0x0 WhitePixel: 0xffffff Font Path: /usr/share/fonts/X11/misc,/usr/share/fonts/X11/100dpi/:unscaled,/usr/share/fonts/X11/75dpi/:unscaled,/usr/share/fonts/X11/Type1,/usr/share/fonts/X11/100dpi,/usr/share/fonts/X11/75dpi,built-ins DPMS (Energy Star): Standby: 600 Suspend: 600 Off: 600 DPMS is Disabled $ xdg-screensaver status disabled