How to Disable GTIN Requirements for Non-Eligible WooCommerce Products

functions.php

<?php
add_filter( 'woocommerce_structured_data_product', 'conditional_identifier_exists_false', 10, 2 );
function conditional_identifier_exists_false( $markup, $product ) {
    // Replace 'your-category-slug' with the actual slug of the category you want to target.
    $target_category_slug = 'your-category-slug';
    
    if ( has_term( $target_category_slug, 'product_cat', $product->get_id() ) ) {
        $markup['identifier_exists'] = 'no';
    }
    
    return $markup;
}