I'm rewriting a large Django project in Java (quarkus + jooq), because it's at the point where I need a type system now, but it still has a place in my heart.
And yes, I guess OP has now a large system that needs types enforced by the system to reduce the friction in evolving the stack.
So have 2 components that ensure the types are correct? Why?
> Note: The Python runtime does not enforce function and variable type annotations. They can be used by third party tools such as type checkers, IDEs, linters, etc.
Then yes, Django model definitions are more like Java types in that they error if you try to use an incorrect type. You can't just ignore them like with type hints.
They also try to be 1:1 with database types, so for the most part any additional validation added on top of Django would be something you had to do anyway.