add_filter( 'rank_math/snippet/rich_snippet_product_entity', function( $entity ) {
    if ( ! is_product() ) {
            return $entity;
    }

    $product = wc_get_product( get_the_ID() );
    if ( ! $product->is_type( 'variable' ) ) {
            return $entity;
    }

    $variations = $product->get_available_variations();
    if ( ! empty( $variations ) ) {
            $offers = [];
            foreach ( $variations as $variation ) {
                    $price_valid_until = get_post_meta( $variation['variation_id'], '_sale_price_dates_to', true );
                    $offers[] = [
                            '@type'           => 'Offer',
                            'description'     => strip_tags( $variation['variation_description'] ),
                            'price'           => $variation['display_price'],
                            'priceCurrency'   => get_woocommerce_currency(),
                            'availability'    => $variation['is_in_stock'] ? 'https://schema.org/InStock' : 'https://schema.org/OutOfStock',
                            'itemCondition'   => 'NewCondition',
                            'priceValidUntil' => $price_valid_until ? date_i18n( 'Y-m-d', $price_valid_until ) : '2025-12-31',
                            'url'             => $product->get_permalink(),
                            'sku'             => $variation['sku'],
                            'color'           => $variation['attributes']['attribute_pa_color'], //name of the attribute
                            'size'            => $variation['attributes']['attribute_pa_size'] //name of the attribute
                    ];
            }
    }

    $entity['offers'] = $offers;

    return $entity;
} );