How to update project when a dependency switches to pure ESM

Question

We are developing a project that uses commonjs. When node-fetch is updated to v3.x, jest complains that:

import fetch, { RequestInfo, RequestInit, Response } from 'node-fetch';

SyntaxError: Cannot use import statement outside a module

npm run build succeeds.

If I use node --experimental-vm-modules node_modules/.bin/jest instead of jest, I get:

Must use import to load ES Module

I did some reading, it appears that we need to migrate our project to be an ESM as well. But it does not appear to be easy.

So the question is: when a dependency becomes pure ESM, how do we handle that in our code?

FYI, our project is: https://gitlab.com/tezgraph/tezgraph