Hi Emmanuel
I think your approach is worth sharing in a blog post, or even a package, rather than adding to Django itself. Your code is worth sharing but may be too specific for the framework.
Unmanaged models aren’t particularly popular. When they are used, it can be for many reasons. As a result, projects may create the tables in various ways during tests, such as loading an existing database dump or calling an external tool. So using Django’s migrations to create them (through managed=True or SchemaEditor) is just one option among many.
Thank you for sharing, and welcome to the Django community!