cadu-book-cpt-menus.php

/**
 * Book CPT for testing purposes
 */
function cpt_book()
{
    register_post_type(
        'cpt_book',
        array(
            'labels'      => array(
                'name'          => __('Books'),
                'singular_name' => __('Book'),
            ),
            'public'      => true,
            'has_archive' => true,
            'rewrite'     => array( 'slug' => 'books' )
        )
    );
}
add_action('init', 'cpt_book');

/**
 * Get all posts for the current user
 */
function cadu_get_current_user_posts()
{
    $userId = get_current_user_id();
    $userPosts = new WP_Query([
        'post_type' => 'cpt_book',
        'post_status' => 'publish',
        'author' => $userId
    ]);
    return (int) $userPosts->found_posts;
}

/**
 * Remove Add New Book Submenu if user has more than one book published
 */
function cadu_remove_admin_menu()
{
    $foundPosts = cadu_get_current_user_posts();
    if ($foundPosts >= 1) {
        remove_submenu_page('edit.php?post_type=cpt_book','post-new.php?post_type=cpt_book');
    }
}
add_action( 'admin_menu', 'cadu_remove_admin_menu' );

/**
 * Remove Add New Button if user has more than one book published
 */
function cadu_remove_add_new_button()
{
    global $current_screen;
    $foundPosts = cadu_get_current_user_posts();
    if (
        ($current_screen->id === 'edit-cpt_book' || $current_screen->id === 'cpt_book')
        && $foundPosts >= 1
    ) {
        echo '<style>
        .wrap .wp-heading-inline+.page-title-action { display: none; }
        </style>';
    }
}
add_action( 'admin_head', 'cadu_remove_add_new_button' );

/**
 * Remove Add New Book if user has more than one book published
 */
function cadu_remove_admin_bar_links() {
    global $wp_admin_bar;
    $foundPosts = cadu_get_current_user_posts();
    if ($foundPosts >= 1) {
        $wp_admin_bar->remove_menu('new-cpt_book');
    }
}
add_action( 'wp_before_admin_bar_render', 'cadu_remove_admin_bar_links' );