Wordpress: reduce to the max

functions.php

<?php

function wp_customize_admin_menu() {
  remove_menu_page( 'edit.php' );
  remove_menu_page( 'edit-comments.php' );
  remove_submenu_page( 'themes.php', 'theme-editor.php' );
  remove_submenu_page( 'plugins.php', 'plugin-editor.php' );
  remove_submenu_page( 'tools.php', 'tools.php' );
  remove_submenu_page( 'tools.php', 'import.php' );
  remove_submenu_page( 'options-general.php', 'options-discussion.php' );
}
add_action('admin_init', 'wp_customize_admin_menu' );

function wp_customize_default_meta_boxes() {
  remove_meta_box( 'authordiv', 'page', 'normal' );
  remove_meta_box( 'commentstatusdiv', 'page', 'normal' );
  remove_meta_box( 'commentsdiv', 'page', 'normal' );
  remove_meta_box( 'postexcerpt', 'page', 'normal' );
  remove_meta_box( 'slugdiv', 'page', 'normal' );
  remove_meta_box( 'trackbacksdiv', 'page', 'normal' );

  remove_meta_box( 'dashboard_quick_press', 'dashboard', 'normal' );
}
add_action('admin_init', 'wp_customize_default_meta_boxes' );

function wp_remove_admin_bar_links() {
    global $wp_admin_bar;
    $wp_admin_bar->remove_menu( 'comments' );
    $wp_admin_bar->remove_menu( 'new-user' );
}
add_action( 'wp_before_admin_bar_render', 'wp_remove_admin_bar_links' );

function wp_init() {
  add_theme_support( 'post-thumbnails' );
  remove_theme_support( 'comments' );

  remove_post_type_support( 'post', 'post-formats' );
  remove_post_type_support( 'post', 'custom-fields' );
  remove_post_type_support( 'post', 'comments' );
  remove_post_type_support( 'post', 'author' );
  remove_post_type_support( 'post', 'trackbacks' );

  remove_post_type_support( 'page', 'custom-fields' );
  remove_post_type_support( 'page', 'comments' );
  remove_post_type_support( 'page', 'author' );
  remove_post_type_support( 'page', 'trackbacks' );
  add_post_type_support( 'page', 'thumbnail' );

  /* Remove 'subscriber' role */
  remove_role( 'subscriber' );

  remove_action( 'wp_head', 'wp_print_scripts' );
  remove_action( 'wp_head', 'wp_print_head_scripts', 9 );
  remove_action( 'wp_head', 'wp_enqueue_scripts', 1 );
  add_action( 'wp_footer', 'wp_print_scripts', 5 );
  add_action( 'wp_footer', 'wp_enqueue_scripts', 5 );
  add_action( 'wp_footer', 'wp_print_head_scripts', 5 );

  /* Remove feed links from head section */
  remove_action( 'wp_head', 'feed_links_extra', 3 );
  remove_action( 'wp_head', 'feed_links', 2 );
  remove_action( 'wp_head', 'rsd_link' );
  remove_action( 'wp_head', 'wp_resource_hints', 2 );
  remove_action( 'wp_head', 'rest_output_link_wp_head', 10 );
  remove_action( 'wp_head', 'wp_oembed_add_discovery_links', 10 );
  remove_action( 'wp_head', 'wlwmanifest_link');
  remove_action( 'wp_head', 'wp_shortlink_wp_head');
  remove_action( 'wp_head', 'wp_generator' );
  remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
  remove_action( 'wp_print_styles', 'print_emoji_styles' );
}
add_action( 'init', 'wp_init' );

add_filter('rest_enabled', '__return_false');
add_filter('rest_jsonp_enabled', '__return_false');

add_filter('jpeg_quality', create_function( '', 'return 85;' ) );

function wp_disable_feed() {
  wp_die();
}
add_action('do_feed', 'wp_disable_feed', 1);
add_action('do_feed_rdf', 'wp_disable_feed', 1);
add_action('do_feed_rss', 'wp_disable_feed', 1);
add_action('do_feed_rss2', 'wp_disable_feed', 1);
add_action('do_feed_atom', 'wp_disable_feed', 1);

function wp_enqueue_scripts() {
  if ( !is_admin() ) {
    wp_deregister_script( 'jquery' );
  }

  wp_enqueue_script(
    'jquery',
    get_template_directory_uri() . '/assets/javascripts/jquery.min.js'
  );

}
add_action( 'wp_enqueue_scripts', 'wp_enqueue_scripts' );

function wp_customice_tiny_mce( $in ) {
  $in['paste_remove_styles'] = true;
  $in['paste_remove_spans'] = true;
  $in['apply_source_formatting'] = false;
  $in['block_formats'] = "Paragraph=p; Heading 1=h1; Heading 2=h2; Heading 3=h3";
  $in['toolbar1'] = 'formatselect,bullist,numlist,bold,italic,underline,strikethrough,alignleft,aligncenter,alignright,alignjustify,link,unlink,charmap,undo,redo,wp_help ';
  $in['toolbar2'] = '';
  $in['toolbar3'] = '';
  $in['toolbar4'] = '';
  return $in;
}
add_filter( 'tiny_mce_before_init', 'wp_customice_tiny_mce' );

// Disable emojis
function disable_emoji_feature() {
	
	// Prevent Emoji from loading on the front-end
	remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
	remove_action( 'wp_print_styles', 'print_emoji_styles' );

	// Remove from admin area also
	remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
	remove_action( 'admin_print_styles', 'print_emoji_styles' );

	// Remove from RSS feeds also
	remove_filter( 'the_content_feed', 'wp_staticize_emoji');
	remove_filter( 'comment_text_rss', 'wp_staticize_emoji');

	// Remove from Embeds
	remove_filter( 'embed_head', 'print_emoji_detection_script' );

	// Remove from emails
	remove_filter( 'wp_mail', 'wp_staticize_emoji_for_email' );

	// Disable from TinyMCE editor. Currently disabled in block editor by default
	add_filter( 'tiny_mce_plugins', 'disable_emojis_tinymce' );

	/** Finally, disable it from the database also, 
	 *  to prevent characters from converting
	 *  Earlier, there was a setting under Writings to do this
	 *  It is not ideal to get & update it here - but it works for now
	 */

	if( (int) get_option('use_smilies') === 1 ) {
		update_option( 'use_smilies', 0 );
	}

}

function disable_emojis_tinymce( $plugins ) {
	if( is_array($plugins) ) {
		$plugins = array_diff( $plugins, array( 'wpemoji' ) );
	}
	return $plugins;
}

add_action('init', 'disable_emoji_feature');
?>