%excerpt%

Hello,

Thank you for contacting Rank Math and bringing your concern to our attention. I’m sorry for any inconvenience this issue may have caused you.

To use the long description on your products, you may need to add this filter on your site:

add_action( 'rank_math/vars/register_extra_replacements', function() {
	rank_math_register_var_replacement(
		'woo_full_desc',
		[
			'name'        => esc_html__( 'Woo Full Desc.', 'rank-math' ),
			'description' => esc_html__( 'Woo Full Description...', 'rank-math' ),
			'variable'    => 'woo_full_desc',
			'example'     => woo_full_desc_callback(),
		],
		'woo_full_desc_callback'
	);
} );
function woo_full_desc_callback() {
	global $post;
	if ( empty( $post ) ) {
		return 'Product Description';
	}

	return wp_strip_all_tags( $post->post_content );
}

Here’s how you can add filter/hook to your WordPress site:
https://rankmath.com/kb/wordpress-hooks-actions-filters/

Once done, you can use the %woo_full_desc% variable in the SEO description field instead of %excerpt%.

Hope that helps.

Hello,

This is the order we follow to generate meta descriptions for WooCommerce products or product categories for that matter:

1. SEO description (Rank Math meta box while editing)
2. Product Short description
3. Single product description (Titles & Meta settings)
4. Product description (long description)

If you want to use the long description above (from your screenshot), then you may need to click the Edit Snippet here and add %woo_full_desc% in the description field.

Also, if you want to force the usage of the meta description you have added in Rank Math > Titles & Meta > Products > Single Product Description, then you may need to add the filter we mentioned here:
https://rankmath.com/kb/how-to-set-product-meta-description/#how-to-set-single-product-description-as-meta-description

After that, set the variable here to use the Product description for all of your products

Looking forward to helping you.