Towards the end TFA claims that Apple’s bundled command line utilities, including zsh and vim, put their dotfiles in ~/.config. They don’t. They put them in the traditional BSD place, the user’s home directory ~/. Looking at mine now, I see .bash_login, .emacs (wow! that’s old), .lldb, .lldbinit, .vimrc, .swiftpm, .z{profile,env,rc} and a few others. I see no ~/.config directory.

My personal practice when writing command line utiities for macOS is to use the macOS API to write settings (previously known as “preferences”) into ~/Library/Preferences, so they can interoperate with any GUI versions of them I might like to write, and for the utilities themselves to have command line options to control those settings. As a sibling comment suggests, you do need to avoid name space collisions. You can use a reverse DNS name, or some companies are big enough just to use their company name. They do appear as .plist files but are actually maintained by a daemon – which nicely avoids race problems with multiple processes updating settings.

If I were writing a portable utility which had a dotfile with a documented format the user was expected to edit, I would make it a dotfile under the home directory.

~/Library/Application Support is really more for per-user static data, like presets and templates, things that are known in a GUI by a string in some dialogue but not necessarily thought of by the user as a file.