add_action( 'after_setup_theme', 'wpc_remove_default_theme_filters', 0 );
function wpc_remove_default_theme_filters() {
    remove_filter( 'woocommerce_upsell_display_args', 'et_divi_woocommerce_output_related_products_args' );
    remove_filter( 'woocommerce_output_related_products_args', 'et_divi_woocommerce_output_related_products_args' );
}


function wpc_et_divi_woocommerce_output_related_products_args( $args ) {
    $related_posts = 5; // default number

    if ( is_singular( 'product' ) ) {
        $page_layout = get_post_meta( get_the_ID(), '_et_pb_page_layout', true );

        if ( 'et_full_width_page' !== $page_layout ) {
            $related_posts = 5; // set to 3 if page has sidebar
        }
    }

    // Modify related and up-sell products args
    $args['posts_per_page'] = $related_posts;
    $args['columns']        = 5;

    return $args;
}
add_filter( 'woocommerce_upsell_display_args', 'wpc_et_divi_woocommerce_output_related_products_args' );
add_filter( 'woocommerce_output_related_products_args', 'wpc_et_divi_woocommerce_output_related_products_args' );