PDF download not retaining font family

  const url = window.URL.createObjectURL(
    new Blob([pdf], {type: 'application/pdf'}),
  );
  const link = document.createElement('a');
  link.href = url;
  link.setAttribute(
    'download',
    `shipping_labels.pdf`,
  );
  document.body.appendChild(link);
  link.click();
  link.parentNode?.removeChild(link);

I am trying to get a string PDF to download automatically, though in converting it to a blob it loses its existing font families; when testing the endpoint that returns the string PDF via Postman, it downloads correctly. How can I retain the font families?