Is it posible with a single REST call to get all the menus and items inside them?
I’m just doing it 1 by 1 and that slows the rendering time. Thats what I have for just one menu:

function get_menu($data)
{
    $args = array(
        'menu'            => $data['slug'],
        'container'       => '',
        'container_class' => '',
        'container_id'    => '',
        'menu_class'      => 'menu-'.$data['slug'],
        'menu_id'         => 'menu-'.$data['slug'],
        'echo'            => false,
        'fallback_cb'     => false,
        'before'          => '',
        'after'           => '',
        'link_before'     => '',
        'link_after'      => '',
        'items_wrap'      => '<ul id="%1$s" class="%2$s">%3$s</ul>',
        'item_spacing'    => 'preserve',
        'depth'           => 0,
        'walker'          => '',
        'theme_location'  => '',
    );
    return array('menu' => wp_nav_menu($args));
}

add_action('rest_api_init', function () {
    register_rest_route('wp/v2', '/menus/(?P<slug>[-w]+)', array(
        'methods' => 'GET',
        'callback' => 'get_menu'
    ));
});

Is there any other ways for doing that? Thanks in advance!