But that’s what you will want to do…follow the guideline, use commands and set up ownership properly.
Use commands would mean codifying the steps, so even the author doesn’t know how to write English, you won’t make one step wrong.
Second thing is, besides you, there are many many little daemons around you and using your computer, just waiting for you to think you are the sole owner and do one wrong step…
Didn’t really look into NixOS so only learned that it is an immutable OS after reading your article.
I once tried Fedora Sericea. Ended up having many Toolboxes (like Distrobox) with libraries and tools for development, but only a couple of Flatpaks.
I think the ideal user for immutable OS will be someone who want to use computer like a smartphone, just install apps (as Flatpaks) and let the OS do its update things.