/* Disable Specific Page from WordPress Sitemap */
function wpflt_sitemap_remove_specific_page($args, $post_type) {
if ('page' !== $post_type) return $args;
$args['post__not_in'] = isset($args['post__not_in']) ? $args['post__not_in'] : array();
$args['post__not_in'][] = 434;
$args['post__not_in'][] = 377;
$args['post__not_in'][] = 375;
$args['post__not_in'][] = 379;
$args['post__not_in'][] = 635;
$args['post__not_in'][] = 389;
return $args;
}
add_filter('wp_sitemaps_posts_query_args', 'wpflt_sitemap_remove_specific_page', 10, 2);
Make sure you update the above code with the proper page ID