I have written the following code which replicates a Google Sheets pivot table in HTML along with the formatting to send out in an email.

issue: getBackgrounds() does not return the colours of the cells of the pivot table (it always returns #FFFFF). I verified the range to be correct, because the table is rendered with the correct amount of rows and columns along with the data values. However without styling. Further, if the colour of a cell is changed manually in the Sheets UI before running the script, then getBackgrounds() will fetch that colour. How can I retrieve the formatting of the pivot table?

code:

function getData(){
  let ss = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("TCD").getRange(5,1).getDataRegion();
  let background = ss.getBackgrounds();
  let val = ss.getDisplayValues();
  let fontColor = ss.getFontColors();
  let fontStyles = ss.getFontStyles();
  let fontWeight = ss.getFontWeights();
  let fontSize = ss.getFontSizes();
  return [val,background,fontColor,fontStyles,fontWeight,fontSize];
}

function setupEmail(attachment, sendBool) {
  let ss_data = getData();
  let data = ss_data[0];
  let background = ss_data[1];
  let fontColor = ss_data[2];
  let fontStyles = ss_data[3];
  let fontWeight = ss_data[4];
  let fontSize = ss_data[5];

  html += "<table border='1' style=\"background-color:#000000;\">"; 
  for (let i = 0; i < data.length; i++) {
      html += "<tr>" 
      for (let j = 0; j < data[i].length; j++) { 
          html += "<td style=\"height:20px;background-color:" + background[i][j] + "; color: " + fontColor[i][j] + "; font-style: " + fontStyles[i][j] + "; font-weight: " + fontWeight[i][j] + "; font-size: " + (fontSize[i][j] + 6) + "px; text-align: center;\">" + data[i][j] + "</td>";
          Logger.log(background[i][j]);
      }
      html += "</tr>";
  }
  html + "</table>"

EDIT: I have worked around this by hardcoding the background-color. If anyone knows why the background colors of a pivot table cannot be returned, please do contribute.