Creating a Google Doc from spreadsheet with the right formatString GAS

Question

With this script I can create a Google Doc from a template and the values in a Google Spreadsheet.

It takes the fields from the active row in the Google Spreadsheet (the one with a highlighted cell or row) and using a Google Doc template (identified by TEMPLATE_ID) creates a doc with these fields replacing the placeholders in the template.

Now, the problem is the format of the cells.
I would to pull in the Google Doc exactly what it appears in the spreadsheet.
With the actual code, if I have:

• in a spreadsheet cell € 18.532,78 ----> in the Google Doc appears 18532,7762
  
• in a spreadsheet cell 300,06 -----> in the Google Doc appears 300.06
  

I would to pull in the Google Doc exactly what it appears in the spreadsheet. How could I solve?
This is the code:

function myFubction() {
  var tableColumn = [3,5]; // Table header is in column C to E
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
  var TEMPLATE_ID = 'xxx';
  var ui = SpreadsheetApp.getUi();
  if (TEMPLATE_ID === '') {        
    ui.alert('TEMPLATE_ID needs to be defined in code.gs')
    return
  }
  var copyFile = DriveApp.getFileById(TEMPLATE_ID).makeCopy();
  var copyId = copyFile.getId();
  var copyDoc = DocumentApp.openById(copyId);
  var FILE_NAME = ui.prompt('Insert the name of Google Doc', ui.ButtonSet.OK);
  copyDoc.setName(FILE_NAME.getResponseText());
  var copyBody = copyDoc.getBody();
  var lastColumn = sheet.getLastColumn();
  var activeRowIndex = sheet.getActiveRange().getRowIndex();
  var activeRow = sheet.getRange(activeRowIndex, 1, 1, lastColumn).getValues()[0];
  var headerRow = sheet.getRange(1, 1, 1, lastColumn).getValues()[0];
  for (var columnIndex = 0; columnIndex < headerRow.length; columnIndex++) {
    if (columnIndex === tableColumn[0] - 1) { // Check if column corresponds to table data
      try {
        var tableValues = sheet.getRange(2, tableColumn[0], sheet.getLastRow()-1,tableColumn[1]-tableColumn[0]+1).getValues();
        var placeholder = `%${headerRow[tableColumn[0]-1]}%`;
        var rangeElement = copyBody.findText(placeholder);
        var element = rangeElement.getElement();
        console.log(element.asText().getText())
        var childIndex = copyBody.getChildIndex(element.getParent());
        console.log(childIndex)
        const elementText = copyBody.getChild(childIndex).asText().getText();
        const [beforeText, afterText] = elementText.split(placeholder);
        copyBody.getChild(childIndex).asText().setText('');
        copyBody.insertParagraph(childIndex, beforeText);
        copyBody.insertTable(childIndex+1, tableValues);
        copyBody.insertParagraph(childIndex+2, afterText);
      } catch(err) {
        continue;
      }
    } else if (columnIndex < tableColumn[0] - 1 || columnIndex > tableColumn[1] - 1) {
      var nextValue = formatString(activeRow[columnIndex]);
      copyBody.replaceText('%' + headerRow[columnIndex] + '%', nextValue);
    }                     
  }
  copyDoc.saveAndClose();
  SpreadsheetApp.getUi().alert('Google Doc created!!')     
}

and this is my menu.gs for formatString;

function formatString(value, options) {

  var formattedValue = value
  options = options || {}

  if (typeof value === 'number') {

    formattedValue = value.toLocaleString('de-DE', {currency: 'EUR', style: 'currency'});
    
  } else if (value instanceof Date) {
  
    var timeZone = Session.getScriptTimeZone()
    var dateFormat = 'dd/MM/yyyy'
    
    if (options.dateFormat !== undefined) {
      dateFormat = options.dateFormat 
    }
    
    formattedValue = Utilities.formatDate(value, timeZone, dateFormat)
    
  } else if (typeof value === 'object') {
  
    formattedValue = JSON.stringify(value)
  }
  
  return formattedValue
}