Issue with importing some object into a nodejs file

So i am working with an api that requires it to be backend called instead of front end called so i have a nodeJs server file called server.js

Right right under my main src folder i have my server.js file

-/ main folder

--/ src

--/ public

--/node_modules

--/ ..other react files like env and package

--/ server.js

this is a form and as the form progresses i have a file called userData.js that gets updated with user response in a json format.

example: Someone presses they live in a single home then the userData.js updates like this

 export const userData = {
  
  'home_type': 'single_home',
  'form_type': 'Neptune D2C Form'
}

When the form gets submitted i have that function like this:

const submitForm = () => {
    fetch('http://localhost:5000/post-form', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(userData),
    })
      .then((response) => response.json())
      .then((data) => {
        console.log('Success:', data);
        navigate('/submit');
      });
}

And in my server.js file the code looks like this:

app.post('/post-form', async (req, res) => {

  const userData = require('./src/data/userData.js');
  const neptuneData = require('./src/data/neptuneData.js')
  
  const url = 'https://uat-api.neptuneflood.com/api/v4/rater/quotes';
  const token = userData.token;


  try {
    const response = await axios.post(url, {
      headers: {
        'Content-Type': 'application/json',
        'Authorization': `Bearer ${token}`
      },
      body: neptuneData
    });

    res.json(response.data);

    console.log('result', response);
  }
  catch (error) {
    res.json({ error: error.toString() });
  }

})

I also have another file called neptuneData.js where i am getting userData.js object and putting them where they belong inside neptuneData.js, neptudeData is where i have the API body parameters like this
EXAMPLE:

export const neptuneData = {
  "isDirectToConsumer": false,
  "application": {
     "addr1": userData.address,
     "city": userData.city,
  }
}

When i try to submit the form i get an error, i have tried to change the way i import userData and neptuneData inside server js, i have tried to add module.exports to userData and neptuneData and things dont seem to work. how can i fix this?

#Errors i am getting

import { userData } from "./userData"
^^^^^^

SyntaxError: Cannot use import statement outside a module

export const userData = {
^^^^^^