Typescript - error when running tsc command for express server

I wanted to know a bit more about typescript and wanted to do a small project with it. I'm running into an error when running the command "tsc app.ts"

1 import express from "express";
         ~~~~~~~

  ../node_modules/@types/express/index.d.ts:133:1
    133 export = e;
        ~~~~~~~~~~~
    This module is declared with using 'export =', and can only be used with a default import when using the 'esModuleInterop' flag.

However I found that when I include the esModuleInterop flag in the tsc command tsc app.ts --esModuleInterop && node app.js - it runs.

I wanted to understand why this was the difference - in the tsconfig.json file I have that flag set to true as well. Was it something that I messed up when setting up typescript?

Below is the tsconfig.json and the package.json file

tsconfig.json:

{
  "compilerOptions": {
        "target": "es2016",
        "module": "commonjs",
        "allowSyntheticDefaultImports": true,
        "esModuleInterop": true,
        "forceConsistentCasingInFileNames": true,
        "strict": true,
        "skipLibCheck": true
    }
}

Package.json

{
  "name": "restapi",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@types/body-parser": "^1.19.2",
    "@types/express": "^4.17.13",
    "body-parser": "^1.19.1",
    "express": "^4.17.2",
    "nodemon": "^2.0.15"
  },
  "devDependencies": {}
}