Separation of application API and heavy calculations?

Question

Node.js

I have a NodeJS (v8 and newer) application. There are two parts - an API for working with the application and a part responsible for complex, long, heavy calculations that take a lot of resources. These calculations are themselves asynchronous and do not depend on the API, but they still load the system as a whole, affecting the speed of the API response. Question: how to separate these two parts so that resource-intensive asynchronous operations do not touch the resources allocated for the API?

Answer 1

2 options:
The win, I think, in a separate server is obvious

Answer 2

run them on two different servers or vps