Suspend Mode

check what your mode is

cat /sys/power/mem_sleep

output: s2idle [deep]

sudo vim /etc/default/grub

append mem_sleep_default=s2idle to GRUB_CMDLINE_LINUX_DEFAULT

GRUB_CMDLINE_LINUX_DEFAULT="(some other options ...) mem_sleep_default=s2idle"

then update grup to apply changes

sudo update-grub

sudo reboot

confirm

cat /sys/power/mem_sleep

output: [s2idle] [deep]