In Product Category archives how to show Posts having same/similar prod_cat slug structure?

Here I’ve written a function for you-

function the_dramatist_get_product_cat_posts( $args = array() ) {
    $default_args = array(
        'taxonomy' => 'product_cat',
        'get_post_type' => 'post'
    );
    $t = array();
    $param = wp_parse_args($args, $default_args);
    $prod_terms = get_the_terms(get_the_ID(), $param['taxonomy']);
    foreach ($prod_terms as $prod_term ) {
        $t[] = $prod_term->term_id;
    }
    $posts = get_posts(array(
        'post_type' => $param['get_post_type'],
        'numberposts' => -1,
        'tax_query' => array(
            array(
                'taxonomy' => $param['taxonomy'],
                'field' => 'id',
                'terms' => $t,
                'include_children' => false
            )
        )
    ));

    return $posts;
}

By calling this function like the_dramatist_get_product_cat_posts() you’ll get all the posts related to current product’s product_cat taxonomy terms. It will give you all the post object. Then you can run a foreach or for loop to organize the posts as you like. You can temporarily do a print_r on this function to understand the returned data structure. It’ll help you to understand the data.

Hope that helps.