Code to Disable “Tag Sitemap” in WordPress

/* Disable Tag Sitemap WordPress */
function wpflt_disable_sitemap_post_tags($taxonomies) {	
	unset($taxonomies['post_tag']);
	return $taxonomies;	
}
add_filter('wp_sitemaps_taxonomies', 'wpflt_disable_sitemap_post_tags');

To disable Tag URLs from WordPress default Sitemap.xml, add this code to child theme’s functions.php

Search Engines do not rely on Sitemaps. They can discover all pages that are accessible to public.