How to show posts from multiple post types in a single loop? And display them separately on the same template

post_type accepts an array.
Have you tried using WP_Query with an array?

$args = array( 
         'post_type' => array( 'product', 'banner', 'portfolio', 'testimonial'),
         'post_status' => 'publish',
         'posts_per_page' => 100
    );
    $the_query = new WP_Query( $args );