Automatic, immediate, no-prompt update installation?

I currently maintain four different installations of Ubuntu Desktop and Pop!_OS (3 and 1, respectively) around my house on various devices. Because of the frequency of package updates, I find myself greeted with “updates are available” pop-ups on one or more desktops on an almost daily basis, which is tedious. Also, I like the idea of having updates automatically applied as soon as available – especially for desktops.

So for those two reasons, I decided to find a way to configure automatic, immediate, no-prompt update installations on all desktops.

  1. I started with the respective Update GUIs on both desktops, but neither offered that feature – only configure of sources and such.

  2. I then did some googling and learned about the “unattended-upgrades” package which is apparently the intended tool for this exact task. I followed the instructions in this article on one desktop as a trial:

    How to set up automatic updates on Ubuntu Server 18.04

It’s been over a week, and I’ve seen no effects. I am still greeted in the morning an “updates available” dialog, and I still have to manually intervene in order to facilitate the installation.

So is there a better way to accomplish this than sticking apt-get update && apt-get -y upgrade in root’s daily cron like a damn caveman?