Python isn't strongly typed so when your codebase grows it tends to be less maintainable than strongly typed code, unless you have a lot of test coverage. But still "doesn't compile" is a very strong indicator your code isn't right.

I would expose the Python code using Flask microservices and do the rest in either Go or Haskell. But I have no idea what needs to be built outside of the data science part. If you have lots of small moving parts you can get away with using Python everywhere since you'll not end up with big balls of code.