Ubuntu - Shutdown does not power-off (tried other solutions)

I noticed recently that shutting down my Linux (Ubuntu 20.04) desktop does not power it down once everything has come to a halt. It states Power down but the led is still glowing and the fan is still moving etc. which it shouldn't! The result is a terminal stating as showin in the picture: I assumed something might be configured wrong in the BIOS but when I tried with Windows (I'm sorry!) it worked as usual so the problem seems to come from the linux side. Of course I searched and tried other solutions like: https://unix.stackexchange.com/questions/457967/shutdown-does-not-power-off-why However neither the KDE shutdown option nor the terminal call seem to work. Another thing I tried was https://askubuntu.com/questions/125844/shutdown-does-not-power-off-computer or https://www.unixmen.com/fix-shutdown-power-computer-ubuntu-14-04/ but the answer seems outdated and does not work (anymore?). So even with the option GRUB_CMDLINE_LINUX_DEFAULT="noplymouth intel_iommu=on acpi=force apm=power_off" nothing happens (tried acpi=force and apm=power_off separately, too) and the computer still stays powered-on after shutting down. One hint might be the output of acpi -V -i > No support for device type: power_supply So is this the problem? Is there a way of configuring acpi correctly? Or did I miss something else? Thanks