Node.js, express if statment running even when the condition is false

I am trying to check whether the signed in user is admin or not. User data is stored in a format like this:

[
  {
    "isAdmin": "true",
    "_id": "60c6df22f25d381e78ab5f31",
    "name": "Admin",
    "email": "admn@xyz.com",
    "password": "$2a$10$dPF0rtehOYXv5aLkmxXgw.99horXCuzbQgvu5ywRaa5C73xQJpaG6",
    "__v": 0,
    "createdAt": "2021-06-14T04:46:26.769Z",
    "updatedAt": "2021-06-14T04:46:26.769Z"
  },
  {
    "isAdmin": "false",
    "_id": "60c6df22f25d381e78ab5f32",
    "name": "Messi",
    "email": "messi@xyz.com",
    "password": "$2a$10$Lkhuz2///oLfrCRMSYoHoeS3QHUCNQDH3OyiN6LyveogGfzldSBDC",
    "__v": 0,
    "createdAt": "2021-06-14T04:46:26.770Z",
    "updatedAt": "2021-06-20T03:45:44.533Z"
  },
]

when the user enter its credentials I am passing adminMiddleware to check wheather isAdmin is false or true. But when I tested it in thunder client I got user data no matter who's bearer token I passed (Admin or normal users).

here is the source code:

adminMiddleware.js

const admin = (req, res, next) => {
  try {
    console.log("Name:", req.user.name);
    console.log("isAdmin:", req.user.isAdmin);
    if (req.user && req.user.isAdmin) {
      next();
    } else {
      const error = new Error("Not Authorized As An Admin");
      error.status = 401;
      next(error);
    }
  } catch (error) {
    next(error);
  }
};

module.exports = admin;

userRoutes.js

const express = require("express");
const {
  registerUser,
  getUsers,
} = require("../controllers/userController");
const protect = require("../middleware/authMiddleware");
const admin = require("../middleware/adminMiddleware");
const router = express.Router();

router.route("/").post(registerUser).get(protect, admin, getUsers);
module.exports = router;

I console logged the isAdmin value for both admin and normal user by there Bearer Token respectively and got:

when isAdmin=false

when isAdmin=true