Could you elaborate on what broke when you updated macOS? Granted, my Nix installation is a single-user installation (so it doesn't have the edited /etc/bashrc and /etc/zshrc that get overridden), but it worked without any issues after I updated from Big Sur to Monterey, so I'm curious about your experience.
The only things that broke for me after the update were the xcode command-line tools, which break for everyone[1].
I imagine GP is talking about every macOS update forcibly overwriting /etc/zshrc.
They bothered writing a system capable of dropping the conflicted file in Relocated Items for us to optionally use--but they appear to be only using it for /etc/bashrc, and not /etc/zshrc. So, people who use zsh by choice or default get dumped on a bit :/
The only things that broke for me after the update were the xcode command-line tools, which break for everyone[1].
[1](https://stackoverflow.com/questions/32893412/command-line-to...)