Just a very negligible contribution. You can use Cython (mind that it is not CPython) to generate shared objects that can interface with C libraries: Interfacing with External C Code — Cython 3.0.11 documentation
For static and dynamic linking instructions, you can find some clues here: Using C libraries — Cython 3.0.11 documentation
To be honest I think using Cython to link external code is not so straightforward, but still it works!
Then you can follow the suggestions above to add a C interface for your Fortran code.