What is the recommendation about using multiprocessing (or multithreading) inside a flask endpoint?

I know that an app server can be configured to:

1. Launch new process per request

2. Launch new thread per request

This question is regarding using python multi-processing (or multi-threading) code inside a flask endpoint. For example say I want to use python multiprocessing for CPU intensive work (or multithreading for IO intensive work).

I have a flask endpoint that takes 40 seconds to run the code (CPU intensive work). I have used python multiprocessing (pool) inside the endpoint code [so that certain CPU intensive things can be done in parallel via multiple processes] and now the endpoints takes 4 seconds to run.

Is it OK to use python multiprocessing (or multithreading) code inside an endpoint when either of the above 2 app server configurations (that is -when the app server is configured to serve each request in a new thread or each new request in a new process). The thread per request is default setting of the flask development server. Where as for gunicorn I can choose either. Is there anything I need to consider when using multiprocessing (or multithreading) inside a flask endpoint so that I am not messing up with the flask process/thread.

from What is the recommendation about using multiprocessing (or multithreading) inside a flask endpoint?