Waking up from deep sleep on Ubuntu

I use Ubuntu on my XPS 13 9000 and because the default sleep mode sleep2idle drains my battery overnight, I tried to set the computer to deep sleep as opposed to the default s2idle.

I first did it using the command echo 'deep' > /sys/power/mem_sleep a couple of weeks ago, which fixed my problem and it was magical, I felt like my laptop was finally behaving like a laptop. After a while it started draining the battery overnight again, since apparently this was only a temporary fix according to this post https://askubuntu.com/questions/1029474/ubuntu-18-04-dell-xps13-9370-no-longer-suspends-on-lid-close.

Then I tried installing sysfsutils and running echo 'power/mem_sleep = deep' > /etc/sysfs.d/mem_sleep.conf, as suggested in one of the comments in the link above (since I didn't feel like messing with the kernel.

Now I am no longer able to wake up from the deep sleep (it hangs on the Dell logo), and I have to restart the computer every time this happens. But it turns out that if I have an external monitor connected to the laptop, I can use the external monitor just fine, only that the laptop screen is unusable as it keeps being stuck at the dell logo. And of course if the external monitor is not connected, I cannot use the computer at all. The exact same problem is reported in this askubuntu post https://askubuntu.com/questions/1237539/dell-xps-improperly-resuming-from-deep-sleep. I tried to even disable the "sign of life" option in the boot options, but this option does not appear under my POST menu and couldn't find it anywhere else.

Help! I am sick of not being able to depend on my laptop because the battery just dies overnight and I refuse to turn it off.