Huh, good to know someone made this:

GitHub - lra/mackup: Keep your application settings in sync (OS X/Linux)

Moving between new setups is always a pain to deal with, especially if there’s new exciting hardware on the horizon with their M4 MacBook Pros and Mac minis. Having something that helps restore your settings for a new setup is always welcome.

I've pretty much accomplished the same thing with what's essentially a (manual) playbook and config files kept in the loop with Syncthing.