Optimization

// Remove default WordPress jquery
wp_deregister_script( 'jquery' );

//Remove jquery migrate
add_action( 'wp_default_scripts', 'remove_jquery_migrate' );
function remove_jquery_migrate( $scripts ) {
	
	if ( ! is_admin() && isset( $scripts->registered['jquery'] ) ) {
			
		$script = $scripts->registered['jquery'];
		
		if ( $script->deps ) { 
			$script->deps = array_diff( $script->deps, array( 'jquery-migrate' ) );
		}
	}
}

if ( ! defined( 'AUTOSAVE_INTERVAL' ) ) {
	// Change 5 to the number of minutes you want to use.
	define( 'AUTOSAVE_INTERVAL', 5 * MINUTE_IN_SECONDS );
}

Disable the auto-generated WordPress Sitemaps added in version 5.5.

add_filter('wp_sitemaps_enabled', '__return_false');

remove_action('wp_head', 'wp_shortlink_wp_head' );

add_action( 'init', function () {

	// Remove the REST API endpoint.
	remove_action( 'rest_api_init', 'wp_oembed_register_route' );

	// Turn off oEmbed auto discovery.
	add_filter( 'embed_oembed_discover', '__return_false' );

	// Don't filter oEmbed results.
	remove_filter( 'oembed_dataparse', 'wp_filter_oembed_result', 10 );

	// Remove oEmbed discovery links.
	remove_action( 'wp_head', 'wp_oembed_add_discovery_links' );

	// Remove oEmbed-specific JavaScript from the front-end and back-end.
	remove_action( 'wp_head', 'wp_oembed_add_host_js' );
	add_filter( 'tiny_mce_plugins', function ( $plugins ) {
		return array_diff( $plugins, array( 'wpembed' ) );
	} );

	// Remove all embeds rewrite rules.
	add_filter( 'rewrite_rules_array', function ( $rules ) {
		foreach ( $rules as $rule => $rewrite ) {
			if ( false !== strpos( $rewrite, 'embed=true' ) ) {
				unset( $rules[ $rule ] );
			}
		}

		return $rules;
	} );

	// Remove filter of the oEmbed result before any HTTP requests are made.
	remove_filter( 'pre_oembed_result', 'wp_filter_pre_oembed_result', 10 );
}, 9999 );

add_filter( 'login_display_language_dropdown', '__return_false' );

add_action( 'init', function () {
	remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
	remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
	remove_action( 'wp_print_styles', 'print_emoji_styles' );
	remove_action( 'admin_print_styles', 'print_emoji_styles' );
	remove_filter( 'the_content_feed', 'wp_staticize_emoji' );
	remove_filter( 'comment_text_rss', 'wp_staticize_emoji' );
	remove_filter( 'wp_mail', 'wp_staticize_emoji_for_email' );

	// Remove from TinyMCE.
	add_filter( 'tiny_mce_plugins', function ( $plugins ) {
		if ( is_array( $plugins ) ) {
			return array_diff( $plugins, array( 'wpemoji' ) );
		} else {
			return array();
		}
	} );

	// Remove from dns-prefetch.
	add_filter( 'wp_resource_hints', function ( $urls, $relation_type ) {
		if ( 'dns-prefetch' === $relation_type ) {
			$emoji_svg_url = apply_filters( 'emoji_svg_url', 'https://s.w.org/images/core/emoji/2/svg/' );
			$urls          = array_diff( $urls, array( $emoji_svg_url ) );
		}

		return $urls;
	}, 10, 2 );
} );

<script type="text/javascript">
//<![CDATA[
jQuery(document).ready(function($) {
$('a').each(function() {
var a = new RegExp('/' + window.location.host + '/');
if(!a.test(this.href)) {
$(this).click(function(event) {
event.preventDefault();
event.stopPropagation();
window.open(this.href, '_blank');
});
}
});
});
//]]>
</script>

add_action('admin_init', function () {
    // Redirect any user trying to access comments page
    global $pagenow;
    
    if ($pagenow === 'edit-comments.php') {
        wp_safe_redirect(admin_url());
        exit;
    }

    // Remove comments metabox from dashboard
    remove_meta_box('dashboard_recent_comments', 'dashboard', 'normal');

    // Disable support for comments and trackbacks in post types
    foreach (get_post_types() as $post_type) {
        if (post_type_supports($post_type, 'comments')) {
            remove_post_type_support($post_type, 'comments');
            remove_post_type_support($post_type, 'trackbacks');
        }
    }
});

// Close comments on the front-end
add_filter('comments_open', '__return_false', 20, 2);
add_filter('pings_open', '__return_false', 20, 2);

// Hide existing comments
add_filter('comments_array', '__return_empty_array', 10, 2);

// Remove comments page in menu
add_action('admin_menu', function () {
    remove_menu_page('edit-comments.php');
});

// Remove comments links from admin bar
add_action('admin_bar_menu', function () {
    remove_action('admin_bar_menu', 'wp_admin_bar_comments_menu', 60);
}, 0);