add_action( 'wp_footer', function() { ?>
  <script type="text/javascript">
    document.addEventListener('DOMContentLoaded', (event) => {
        var videos = document.querySelectorAll('video');
        videos.forEach(function(video) {
            video.controlsList.add('nodownload');
        });
    });
  </script>
  <style type="text/css">
    video::-internal-media-controls-download-button {
      display: none !important;
    }
  </style>
<?php } );