This is a good point, not having these protected functions is a limitation that I also encounter very often.
For application code, I use boundary, it’s an extremely powerful concept to separate the internal functionality of a feature and create a public interface. I never tried to use a library that uses boundary, but I think it might work as well.
It doesn’t do any magic besides checking if you have boundary violations in your codebase, so it cannot make documentation private. I am not entirely sure, but I think you could disable documentation for unwanted modules by just doing @moduledoc false.
