I am trying to make an API endpoint called GET where an application can resolve a file from an id if it is authenticated by the middleware authenticateUser, the problem is that express can not seem to recognize the URL parameter id

I have tried adding the parameter in different files, for more context there is two files, a router.ts file and download.ts

Contents of download.ts

import client from "../config/database"
import { Router, Request, Response } from "express"
import authenticateUser from "../utils/auth"
const router = Router()

router.get(
  "/:id",
  authenticateUser,
  async (res: Response, req: Request) => {
    const fileId = req.params.id
    

    const file = await client.query(
      "SELECT userid FROM files WHERE id = $1",
      [
        fileId
      ]
    )
    if (file.rows[0].userid == req.user.id) {
      res.download("../uploads/" + req.params.id)
      return res.status(200).send()
    } else {
      return res.status(401).send()
    }
  }
)

export default router

And contents of router.ts

import { Router } from "express"

import signup from "./signup"
import login from "./login"
import upload from "./upload"
import download from "./download"
import ping from "./ping"
import new_dir from "./newDirectory"

const router = Router()

router.use("/signup", signup)
router.use("/login", login)
router.use("/upload", upload)
router.use("/download/", download)
router.use("/ping", ping)
router.use("/new_dir", new_dir)

export default router

As previously mentioned, I have tried adding the parameter in different files like this
I tried adding the id parameter in router.ts like this

router.use("/download/:id", download)

Which wasn’t recognized and is seen as undefined
And tried adding it in the download.ts

router.get(
  "/:id",
  authenticateUser,
  // Main func here
)

Reading this question, I have modified the code like this in router.ts

router.use(
  "/download/:id", 
  (req, res, next) => { // Add a function to assign request params to another variable that can be read by the handler
    req.parameters = {}
    req.parameters.fileId = 2
    next();
  },
  download
)

But the error still persists stating that the variable is undefined there is no obvious solution I can find.
Here is the full log from the terminal

D:Websitespicture-upload-download-platformbackendnode_modulesexpresslibrouterlayer.js:95
    fn(req, res, next);
    ^
TypeError: Cannot read properties of undefined (reading 'fileId')
    at D:Websitespicture-upload-download-platformbackendsrcroutesdownload.ts:10:35
    at Layer.handle [as handle_request] (D:Websitespicture-upload-download-platformbackendnode_modulesexpresslibrouterlayer.js:95:5)
    at next (D:Websitespicture-upload-download-platformbackendnode_modulesexpresslibrouterroute.js:149:13)
    at authenticateUser (D:Websitespicture-upload-download-platformbackendsrcutilsauth.ts:37:5)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)

Everything I have tried hasn’t worked. Sorry in advance, I am still new to asking questions so forgive me if the question is not clear or improperly formatted 🙁