Recent update in Kali linux is having one problem with the auto suspend operation. Even the power settings are perfect (Automatic suspend = Off), the computer sleeps every 20 minutes.
Steps to perform to disable auto sleep:
cd /usr/share/gdm/dconf vi 90-debian-settings
Search for below parameters, uncomment if commented. Set the value to 0.
Once done, run below command to refresh the settings:
dconf compile /var/lib/gdm3/greeter-dconf-defaults /usr/share/gdm/dconf
The issue should be resolved !! If not, please comment below. Will look into the issue.