A kernel update didn't generate the initramfs

This sounds like a bug on Nix configuration, or the kernel build process.

If NixOS had caught the error, you wouldn't have gotten a faulty generation at all. This is different from pacman/apt/dnf, which will happily continue the upgrade, resulting in a broken system with no easy way to fix it.

I haven't installed gentoo in 20 years. I still like arch for it's glaring flaws. And I do like BSDs ports etc. I probably should go through a gentoo install again to see how it changed. Last time I ran it. Was on a first generation Pentium.

Upgrade will upgrade the system to whatever is newest in your package cache. If, for example, you've just performed a partial upgrade and put yourself into an unsupported state, running upgrade without first running update will put your system back in line with itself.

There probably almost never a reason for this, but its the equivalent of running pacman -u which under normal circumstances you will never do

Or the Linux firmware package change that required manual intervention to resolve.

Checks 'automatic updates' box in Discover

On a beefy machine it's nice. Chromium takes forever.

The second y in Syyu is almost always unneeded and just wastes time and bandwidth. Is i remember correctly, it only makes sense when for example you switch mirrors

I think Fedora's COPR carries on the torch, besides Arch's AUR. But generally, yeah, avoid PPA's like the plague. It's been garbage for years now. You'd be better off actually compiling the software yourself.

I thought I remembered that correctly from my time with Ubuntu like 20 years ago.

Upgraded three systems to Debian 13 in the last few days. Went without a hitch. One Proxmox, one media server and player, one workstation.

Wayland still doesn't work, but that's apparently because of the noVideo drivers.