"require() of ES Module [...] is not supported" when using typescript

Question

My setup is as follows:

I have a package.json file:

{
  "name": "discord-app-test",
  "version": "1.0.0",
  "main": "src/index.ts",
  "license": "ISC",
  "scripts": {
    "dev": "nodemon --exec \"yarn start\" --watch src --ext ts,json --ignore *.test.ts",
    "start": "ts-node ."
  },
  "dependencies": {
    "dotenv": "^10.0.0",
    "node-fetch": "^3.0.0"
  },
  "devDependencies": {
    "@types/node": "^16.11.6"
  }
}

I have no tsconfig.json file as I never need it, normally. Though, somehow when using the node-fetch package, I get this error saying "require() of ES Module [...] is not supported" even though I am importing it with the ES6 syntax:

import fetch from 'node-fetch';

I have tried specifying "type": "module" in my package.json, but then I got the error "Unknown file extension ".ts" for [...]".