How to generate URL from @app.route url in FLASK?

I have a Flask code with decorator @app.route(/bestApp) to fetch my data from Fetch API javascript.

this is my app.py :

@app.route('/bestApp', methods=['GET', 'POST'])
def bestapp():
   app_data = AppDataFromUrl(app_url)
   json.dumps(app_data)
   permitted_directory='static/assets/upload/'
   return send_from_directory(directory=permitted_directory, path=filename,as_attachment=True)

and this is my script.js

async function getExtract() {
  try {
    const response = await fetch("/bestApp", {
      method: "post",
      body: new FormData(document.querySelector(".testform")),
    });

    console.log(response);
	
	}

whenever i download my file, it works but the problem is the link that shown in browser is like “http://127.0.0.1:5000/bestApp

how to convert http://127.0.0.1:5000/bestApp to normal URL? such http://127.0.0.1:5000/42342jnkjsahdkajsda87391237921dask.

I don’t wanna use Blob Object Url or Data URI.