So I got a solution for you that might work!
#First you are gonna need to download the Autopoweroff package
wget https://github.com/deragon/autopoweroff/releases/download/3.0.0/autopoweroff-3.0.0-1.noarch.deb
#Then install it using
sudo dpkg -i autopoweroff-3.0.0-1.noarch.deb
sudo apt-get install -f
Then if you are using GNOME just look up autopoweroff in the activities, else go to /etc/autopoweroff/autopoweroff.conf.dpkg-new and modify the idle time as a sudo user!
If you use the file to modify the idle shutdown settings, here is what I did
[NO_SHUTDOWN_TIME_RANGE]
StartHour=
EndHour=
# StartupDelay parameter (expressed in minutes):
#
# When the computer is booting up, if all the conditions are met and
# the computer is in the shutdown time range, as soon as Autopoweroff
# is started, the computer will shutdown. Thus, the user will never
# have the chance to boot into the computer. This is where the
# "delay" parameter comes in. If "delay" is set to 15 for example,
# Autopoweroff will not poweroff the computer even if all the
# conditions are met, for a period of 15 minutes after the computer
# has booted. This allows the user to login and change Autopoweroff's
# configuration.
#
#
# IdleTime parameter (expressed in minutes):
#
# Like a screensaver, Autopoweroff detects keyboard and mouse
# activity, and if there is any activity on the server, it would not
# be powered off regardless if all the other conditions are met. If
# set to 0, user activity on the server will be ignored.
[TIMEOUTS]
StartupDelay=5
IdleTime=30
#Part of the info was obtained here
https://www.ostechnix.com/auto-shutdown-reboot-suspend-hibernate-linux-system-specific-time/