how to convert theme template part to custom elementor widget?

Question

Actually I want to add my custom widget to my custom theme template part as global but without saving as global value embed as shortcode is it possible? If yes so how ?

<?php
 $widgets_manager = \Elementor\Plugin::$instance->widgets_manager;
    $widget_class = $widgets_manager->get_widget_types()['exe-list'];
    ob_start();
    $widget_class->render();
    $output = ob_get_clean();
    return $output;
?>

But giving error Tying to access array offset on value of type null in C:\wamp64\www\bc-exe\wp-content\plugins\elementor\includes\base\controls-stack.php on line 1576 Call Stack