I think I didn't make it clear enough: My laptop was on the power during the update process, when the power randomly cut out - for the first time in about 6 years, it doesn't happen often. Of course you can interpret it as user error - but I think it's reasonable to update my system when plugged into, normally reliable power. The laptop battery is pretty much dead, so it would've shut itself down automatically anyway.
If you're planning for this type of failure, what you probably want instead is Aurora from the Universal Blue project. Since it's fedora silverblue underneath, your OS either updates all at once or doesn't.
This is why you keep a backup kernel
When I used Arch I updated once and it removed the running kernel and its modules. So when I plugged in a webcam it didn't work, since the module was gone.
Not a catastrophe, but it was an off-putting user experience coming from Debian. Arch felt more like a desktop OS, Debian feels more like a server OS to me (updates generally warn/confirm when you need to restart services or the machine).
To each their own! Having more up to date stuff was a nice perk of running Arch, certainly.
This got me looking to see if there is any way to have a fallback as I have had something similar happen to me.
The general advice is to have a liveboot USB around. I even saw that you can have GRUB simply boot from an .iso file on the internal drives, which eliminates the need to keep a USB stick around.
I haven't followed the steps yet but I'll give this a shot because it intrigues me.
https://www.linuxbabe.com/desktop-linux/boot-from-iso-files-using-grub2-boot-loader
I was installing Nobara 40 and discovered that the live session is allowed to suspend the PC during the install process. The system ended up having problems with some basic functions...
