Once #nixos installed, what to do ?
stable or unstable ? #homemanager or not ?
#flakes or not ? Multiple files for my configuration.nix or not ?
According to your use, some of this questions can be answered here :
https://discourse.nixos.org/t/tips-tricks-for-nixos-desktop/28488
Now I've different approach for my laptop (all in configuration.nix) and my servers (multiple files) : #kiss (Keep It Stupid Simple)