Generate PDF from a Template with sheet data including graphics

Question

I have a script that takes information from a spreadsheet, replaces the text in a "template" document and generates a PDF for later sending by email. See an excerpt of my code below:

 // Cria o novo documento, recupera o ID e o abre
  var idCopia = DriveApp.getFileById(idTemplate).makeCopy(nomeDoArquivo).getId();
  var docCopia = DocumentApp.openById(idCopia);

  // recupera o corpo e o rodapé do documento
  var bodyCopia = docCopia.getBody();
  var footerCopia = docCopia.getFooter();
  
  // faz o replace das variáveis do template, salva e fecha o novo documento
  bodyCopia.replaceText('%MESREF%', docMesRef);
  bodyCopia.replaceText('%PERIODO%', docPeriodo);
  bodyCopia.replaceText('%CLIENTE%', docCliente);
  bodyCopia.replaceText('%DATAREL%', docDataRel);
  footerCopia.replaceText('%CONTRATO%', docContrato);
  docCopia.saveAndClose();
  
  

    // abre o documento temporario como PDF utilizando o seu ID
    var pdf = DriveApp.getFileById(idCopia).getAs("application/pdf");

I didn’t glue the whole job together because it’s too big. The important thing is to know that the script, in this section, collects the spreadsheet data, replaces expressions in a template file (for example: %word%), saves and generates a PDF copy.

However, I need to include in this document 4 graphs that were generated in this same spreadsheet. I’ve done a lot of research and can’t find a clean alternative to doing this.

Currently, I inserted these 4 linked charts in the template file. So before I run the script, I open the template, update the 4 charts and only then run the script to generate the PDF of that template, with the updated graphics. Obviously, this alternative is very dumb on my part, but I couldn’t find a way to update these graphics via script.

I would like to run this script and also insert the 4 charts or update the existing ones in the template so that, when generating the PDF, is correct.

I ask for help from the community!