Only 4 related products are shown

Hi @makeupedia ,

Thanks for contacting us.

Can you please be more specific with some screenshots of the backend settings and frontend situation on your site? It’s best if you can provide your site link or link to the page with custom related products so that I can help you?

Best regards.

You also can try to add below function to current theme (or child-theme) / functions.php

add_filter( 'woocommerce_output_related_products_args', 'woocr_related_products_args' );
function woocr_related_products_args( $args ) {
	$args['posts_per_page'] = 9;

	return $args;
}