I would like to see there is an feature like
hugo convert, which convert the front matter to specified format, but for configurations (single configuration file and configuration directories).
It’s useful for clients to choose their preferred format when creating a site with the theme template that configure in other format.
This seems like a lot of work for a very small return. There are many online converters, and some code editor extensions (e.g., convert json, yaml, xml, and others - Visual Studio Marketplace).
You would also remove all comments when changing from one format to another. For some themes, that would remove most of their documentation.