I don't understand how to set 404 page for any start number route and don't route to default index page.
If I goto https://localhost/404 (or any numbers), I see default index page, not 404 page.
This route:
    $di->set('router', function () {
        $router = new Router(false);
        $router->setDefaultModule('frontend');
        $router->add('/:action', [
            'module' => 'frontend',
            'controller' => 'index',
            'action' => 1,
        ]);
        $router->add('/:action/:params', [
            'module' => 'frontend',
            'controller' => 'index',
            'action' => 1,
            'params' => 2,
        ]);
        $router->add('/:module/:controller/:action/:params', [
            'module'     => 1,
            'controller' => 2,
            'action'     => 3,
            'params'     => 4,
        ]);
        $router->removeExtraSlashes(true);
        return $router;
    });
And this dispatcher exception for default frantend module:
        $dependencyInjector->setShared(
            'dispatcher',
            function () {
                $eventManager = new Manager();
                $eventManager->attach(
                    'dispatch:beforeException',
                    function ($event, $dispatcher, $exception) {
                        switch ($exception->getCode()) {
                            case Dispatcher::EXCEPTION_HANDLER_NOT_FOUND:
                            case Dispatcher::EXCEPTION_ACTION_NOT_FOUND:
                                $dispatcher->forward([
                                    'controller' => 'error',
                                    'action' => 'notFound',
                                ]);
                                return false;
                        }
                    }
                );
                $dispatcher = new Dispatcher();
                $dispatcher->setDefaultNamespace('AudioOcean\Frontend\Controllers');
                $dispatcher->setEventsManager($eventManager);
                return $dispatcher;
            }
        );