Managing SECRET_KEY_BASE without Kubernetes/Docker/etc?

That’s stored in the application data directory, unless overridden by environment for some ad-hoc reason (such as being run in a deployed, managed, Linux-based or containerized environment).

database_path =
  System.get_env("DATABASE_PATH")
  || Path.expand("fooApp.db", :filename.basedir(:user_data, "fooApp"))

I’d really like it if the application I’m writing did not offload these “hoops to jump through”, as you put it, to the installing technician.

The existing version of the application I’m writing a replacement for “just works”: you unzip it and run it, and it generates defaults for its own config and state files if needed, which is (in my experience using non Elixir based programs) an almost completely universal standard; are you telling me there’s no best practice pattern for implementing that with Phoenix?