Give WP editors access to edit menus and only menus

functions.php

// Allow editors to see access the Menus page under Appearance but hide other options
function hide_menu() {
 	$user = wp_get_current_user();

	// Check if the current user is an Editor
	if ( in_array( 'editor', (array) $user->roles ) ) {

		// They're an editor, so grant the edit_theme_options capability if they don't have it
		if ( ! current_user_can( 'edit_theme_options' ) ) {
			$role_object = get_role( 'editor' );
			$role_object->add_cap( 'edit_theme_options' );
		}

		// Hide the Themes page
	    remove_submenu_page( 'themes.php', 'themes.php' );

	    // Hide the Widgets page
	    remove_submenu_page( 'themes.php', 'widgets.php' );

	    // Hide the Customize page
	    remove_submenu_page( 'themes.php', 'customize.php' );

	    // Remove Customize from the Appearance submenu
	    global $submenu;
	    unset($submenu['themes.php'][6]);
	}
}

// Remove customize from the admin bar
function remove_customize()  {
	global $wp_admin_bar;
	$wp_admin_bar->remove_menu('customize');
}

// Remove the additional CSS section
function remove_css_section( $wp_customize ) {
	$wp_customize->remove_section( 'custom_css' );
}

$user = wp_get_current_user();
if ( in_array( 'editor', (array) $user->roles ) ) {
    add_action('admin_menu', 'hide_menu', 10);
    add_action('wp_before_admin_bar_render', 'remove_customize');
    add_action( 'customize_register', 'remove_css_section', 15 );
}