Google Tag Manager

Load Realific through Google Tag Manager.

Create a Custom HTML tag:

<script>
  (function () {
    var s = document.createElement('script');
    s.defer = true;
    s.src = 'https://realific.app/r.js';
    s.setAttribute('data-site', 'YOUR_PUBLIC_KEY');
    document.head.appendChild(s);
  })();
</script>

Trigger it on All Pages (Initialization) and publish the container. Loading the script directly in your HTML is still faster and more resilient to blockers.