Think you should use a different mindset when using EOS , it is more of a Diy distro then Ubuntu.
Besides the update notifier is no longer maintained, and does not always work the way it should.
Maybe you could recommend something more up-to-date and supported? For example, gnome-shell-extension-arch-update.
I use Arch Update Checker to monitor updates. I use yay to actually perform the updates though.
checkupdates is part of the pacman package if I remember correctly and is installed by default. This will give you all OFFICIAL updates at the command line. There are “notifiers” however you could make your own. Personally I just have updates display on a conky this way I can see that there are updates.
checkupdates This by itself will show all available updates
checkupdates | wc -l Will display the number of updates available.