Additional Scope and REST Api Queries?

I have made my research before opening this thread . Here is what I am trying to achieve .

Edit : A bit more context:
Iam building a product management tool for Prestashop CSM. One of the functionalities imply creating products from a table created from user input .

In my web app want to send a POST Api request in XML for each row of a table to a private endpoint ( with authentification ) from a webapp.

I've created the API request query with the right setting for xml bady and performed a request : it works . To be able to send a request for each row I followed the guide here. I created another query called "query3" to trigger query2 (the REST api query ). As for the body of the request i left it empty and referenced {{}} and the code to trigger the API query is :

    additionalScope: {
  data: `[...**the xml body goes here** ]`

But in the query3 query there is no way to add an additional scope unlike sql Queries and javascript queries or am I missing something .

here is the full code :

var errors = "";
var total = rows.length;
var rowImported = 0;
var result = '';

function runQuery(i) {
  // Update the Status text
 result += "Progress: " + (i.toString() + "/" + total.toString()); 

  if (i >= rows.length) {
    console.log("Finished running all queries");
  rowImported += 1;
  console.log("Running query for row", i);
  let cats = rows[i].catégories?rows[i].catégories.split():undefined;

    additionalScope: {
  data: `[...**XML BODY GOES HERE** ]` },

    onSuccess: function (data) {
      // Make the API request
      // run query for next rows 
     // runQuery(i + 1);
    onFailure: function (error) {
      // Update the Errors text
      errors += "Found error at line " + i.toString() + ":  " + error + "\n\n";
      runQuery(i + 1);


return errors```

Update: I succeed sending the request using the additional scope - Solution: I had to place it inside the raw body - no headers.