Nodejs middleware to bypass CORS

Question

I had an issue posing to an external backend from my REACT app due to a CORS error.

Access to XMLHttpRequest at 'https://testsecureacceptance.cybersource.com/pay' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

I decided on this solution https://stackoverflow.com/a/60908929/14287707 that uses nodejs as a middleware .The external endpoint I am posting to is "https://testsecureacceptance.cybersource.com/pay" which upon success redirects to "/checkout" that opens a checkout page. My nodejs is running on localhost:5000 while my REACT is running on localhost:3000 . I am convinced there's smt I am missing given its my first nodejs app and would love an extra pair of eyes to guide here. So localhost:5000 gets hit and returns a status code 302 redirect. But /checkout still gives me the error - "Access to XMLHttpRequest at 'https://testsecureacceptance.cybersource.com/checkout' (redirected from 'http://localhost:5000/') from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested"

REACT

export default function Absa() {

  const [result, setResult] = useState(null);

  const [checkout, setCheckout] = useState(null);

  const {uuid} = useParams();

  const absa = async () => {
    try{
      let res = await axios.get(`${process.env.REACT_APP_PAYMENT_URL}/signed_data/${uuid}`)

      setResult(res.data);
    } catch (e) {
      console.log(e)
    }
  }
  ;

  useEffect (() =>{
    absa()
  },[])

const qs = require('qs');

  const postData = (e) =>{
    e.preventDefault();
    axios.post('http://localhost:5000',

  qs.stringify({ ...result }),
  
  ).then(response => {

    if (!response.data){
      throw Error("ERROR");  
    }
    let responseHtml = response.data;
    
   //open the new window and write your HTML to it
    var myWindow = window.open("", "response", "resizable=yes");
    myWindow.document.write(responseHtml);
   
  })
  .catch(error => console.log(error));
  
  };

node js

const express = require('express'); //Import the express dependency
var cors = require('cors')
const app = express();              //Instantiate an express app, the main work horse of this server
app.use(cors());
const port = 5000;                  //Save the port number where your server will be listening

const { createProxyMiddleware } = require('http-proxy-middleware');
app.use('/', createProxyMiddleware({ 
    target: 'https://testsecureacceptance.cybersource.com/pay', //original url
    changeOrigin: true, 
    //secure: false,
    onProxyRes: function (proxyRes, req, res) {
       proxyRes.headers['Access-Control-Allow-Origin'] = '*';
    }
}));


app.listen(port, () => {            //server starts listening for any attempts from a client to connect at port: {port}
    console.log(`Now listening on port ${port}`); 
});