Someone on the PyO3 GitHub posted a link to a project they started which claims to use a Interpreter Pool to allow for multiple Python callbacks to execute simultaneously: https://github.com/PyO3/pyo3/issues/576#issuecomment-1713039140 @flat-zoo-31952 maybe worth a look until PyO3 supports sub-interpreters fully, or we get nogil

I'm not an expert here but it seems like you might need to start the python interpreter from a rust frame? https://github.com/letalboy/RustPyNet