How to quickly scan two Google drive folders and copy any missing files from a source folder to the target folder?

Question

I have a script that will scan the source and target folders on Google Drive but it takes a long time to run (400 seconds or more).

Below is the code used to scan the source one file and one folder at a time and then look in the target drive to see if the file or folder exists. If it does not, then the file is copied or a folder is created.

I'd like a script to much more quickly scan a source drive and to scan a target drive and to copy any missing files from source to target.

function copyFilesRecursively() {
    var sourceFolderId = '###source UID###';
    var destinationFolderId = '###target UID###';
  
    var sourceFolder = DriveApp.getFolderById(sourceFolderId);
    var destinationFolder = DriveApp.getFolderById(destinationFolderId);
  
    copyFolderContents(sourceFolder, destinationFolder);  
  
}

function copyFolderContents(source, destination) {
  var folders = source.getFolders();
  
  while (folders.hasNext()) {
    var subFolder = folders.next();
    var existingFolder = getFolderByName(destination, subFolder.getName());

    var newFolder;
    if (existingFolder) {
      newFolder = existingFolder;
    } else {
      newFolder = destination.createFolder(subFolder.getName());
    }

    copyFolderContents(subFolder, newFolder);
  }
  
  var files = source.getFiles();
  
  while (files.hasNext()) {
    var file = files.next();
    copyFile(file, destination);
  }
}

function copyFile(sourceFile, destinationFolder) {
  // Check the MIME type of the source file
  var sourceMimeType = sourceFile.getMimeType();

  // Check if the source file is a Google Apps Script - if it is, then do not copy it
  if (!(sourceMimeType === 'application/vnd.google-apps.script')) {
    // Source file is not a Google Apps Script, proceed with copying

    // Check if a file with the same name already exists in the destination folder
    var destinationFiles = destinationFolder.getFilesByName(sourceFile.getName());

    if (! destinationFiles.hasNext()) {
      // File doesn't exist in the destination, create a new one
      var newFile = destinationFolder.createFile(sourceFile.getBlob());
      newFile.setName(sourceFile.getName());
    }
  }
}

function getFolderByName(parentFolder, folderName) {
  var folders = parentFolder.getFoldersByName(folderName);
  return folders.hasNext() ? folders.next() : null;
}

Any suggestion on how to only copy missing files MORE quickly?