Add a simple cart count to the Pro header builder cart elements

pro-cart-count.php

<?php

// Add cart count and value to Cart Element text in a Pro header
// =============================================================================
add_filter('woocommerce_add_to_cart_fragments', 'mb_cart_count_fragments', 10, 1);
function mb_cart_count_fragments($fragments) {
	$count = WC()->cart->get_cart_contents_count();
	$fragments['.cartdropdown .x-anchor-text-primary'] = '<span class="x-anchor-text-primary">' . $count . '</span>';
	return $fragments;
}

style.css

.cartdropdown .x-anchor-text {
  position: absolute;
  top: -5px;
  right: -5px;
  background: #9ccf80;
  border-radius: 1em;
  width: 20px;
  height: 20px;
  text-align: center;
  color: #fff;
  line-height: 1.2;
  z-index: 10;
  opacity: 0;
  pointer-events: none;
}
body.cart-has-items .cartdropdown .x-anchor-text {
  opacity: 1;
}