For me, this is the holy grail. Every time I switch laptops, I lift all my config files and such over, but there's always so many system level configs and other things that you have to go and manually fiddle. On top of that, some apps don't really behave well when you just move config files to e.g. under a different username etc. Would be nice if there was a comprehensive solution to this problem, need to try nix-darwin out.

nix-darwin is essentially this. I have a small bootstrap script to install Xcode CLI and Nix, git clone my dotfiles and activate the config. That in turn sets up the system, also installs Homebrew, installs apps from the App store and sets up all my configs. The only thing I need to do after is sign into some accounts.