How to disable the behaviour of the power button on Ubuntu 20LTS

I disabled the power button on my desktop (pressing it did nothing, no shutdown, no hibernation/sleep, because my kids like it to press)
After I upgraded my ubuntu from 18LTS to 20LTS, the disabled power button behaviour does not work anymore. When it is pressed, it hibernates the PC.

Here are my current settings gsettings list-recursively org.gnome.settings-daemon.plugins.power

org.gnome.settings-daemon.plugins.power lid-close-ac-action 'suspend'
org.gnome.settings-daemon.plugins.power time-critical 300
org.gnome.settings-daemon.plugins.power power-button-action 'nothing'
org.gnome.settings-daemon.plugins.power lid-close-suspend-with-external-monitor false
org.gnome.settings-daemon.plugins.power button-hibernate 'nothing'
org.gnome.settings-daemon.plugins.power idle-dim true
org.gnome.settings-daemon.plugins.power button-power 'nothing'
org.gnome.settings-daemon.plugins.power lid-close-battery-action 'suspend'
org.gnome.settings-daemon.plugins.power priority 0
org.gnome.settings-daemon.plugins.power idle-brightness 30
org.gnome.settings-daemon.plugins.power active true
org.gnome.settings-daemon.plugins.power critical-battery-action 'suspend'
org.gnome.settings-daemon.plugins.power button-suspend 'nothing'
org.gnome.settings-daemon.plugins.power button-sleep 'nothing'
org.gnome.settings-daemon.plugins.power percentage-critical 3
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-timeout 3600
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type 'nothing'
org.gnome.settings-daemon.plugins.power ambient-enabled true
org.gnome.settings-daemon.plugins.power notify-perhaps-recall true
org.gnome.settings-daemon.plugins.power percentage-low 10
org.gnome.settings-daemon.plugins.power percentage-action 2
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-type 'suspend'
org.gnome.settings-daemon.plugins.power time-low 1200
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-timeout 1200
org.gnome.settings-daemon.plugins.power time-action 120
org.gnome.settings-daemon.plugins.power use-time-for-policy true

cat /etc/systemd/logind.conf

[Login]
#NAutoVTs=6
#ReserveVT=6
#KillUserProcesses=no
#KillOnlyUsers=
#KillExcludeUsers=root
#InhibitDelayMaxSec=5
HandlePowerKey=ignore
HandleSuspendKey=ignore
HandleHibernateKey=ignore
#HandleLidSwitch=suspend
#HandleLidSwitchDocked=ignore
#PowerKeyIgnoreInhibited=no
#SuspendKeyIgnoreInhibited=no
#HibernateKeyIgnoreInhibited=no
#LidSwitchIgnoreInhibited=yes
#HoldoffTimeoutSec=30s
#IdleAction=ignore
#IdleActionSec=30min
#RuntimeDirectorySize=10%
#RemoveIPC=yes
#InhibitorsMax=8192
#SessionsMax=8192
#UserTasksMax=33%

Have you any ideas what could be wrong?
Thank you for your help.

I am not sure what is wrong with your files.

1. The logind-way

   Did you try

   sudo systemctl restart systemd-logind
   

   or (better) rebooting?

2. The acpid-way

   Besides, this a possible method to obtain the behaviour you are looking for. Create an ACPI handler with a file in /etc/acpi/events/

   sudo nano /etc/acpi/events/powerbtn-acpi-support
   

   (Note: as per official info, "Rules are defined by simple configuration files. acpid will look in a configuration directory (/etc/acpi/events by default), and parse all regular files that do not begin with a period ('.') or end with a tilde (~).")

   Make that file contain

   event=button[ /]power
   action=
   

   Then restart the acpi daemon with

   sudo service acpid restart
   

Notes:

3. The cardboard-way is funny.

Sources:

https://superuser.com/questions/1523918/run-script-when-power-button-pressed

https://wiki.archlinux.org/index.php/acpid

How to prevent the Power button to shutdown directly the system?

https://superuser.com/questions/699905/change-behavior-of-linux-power-button/699925

Ubuntu 20.04 LTS has it in the GUI controls. There is an option to make the power button "Do nothing" in the Power Button Behavior dropdown menu.
*

Check to see if there are other desktop environments in play like:
com.canonical.unity.settings-daemon.plugins.power
or
org.mate.power-manager

You may have made the correct change, but for the wrong environment...

a more generic search of your gsettings can also help:
gsettings list-recursively | grep button on my system additionally yields:
.
.
.
com.canonical.unity.settings-daemon.plugins.power power-button-action 'suspend'
com.canonical.unity.settings-daemon.plugins.power button-hibernate 'hibernate'
com.canonical.unity.settings-daemon.plugins.power button-power 'suspend'
com.canonical.unity.settings-daemon.plugins.power button-suspend 'suspend'
com.canonical.unity.settings-daemon.plugins.power button-sleep 'hibernate'