In short, I learned recently about Objects for Type Hinting in Qiskit/rustworkx#1345 and they are not available in pyo3-ffi. Those specific types have been part of the Stable ABI since 3.9.

Currently, I can still achieve my goals by importing types.GenericAlias via the Python interpreter but I still think typing objects deserve to be included.

I am willing to contribute the Rust bindings if they are welcome.