Hide product price and disable add to cart for specific product categories in Woocommerce

Your existing code is complicated, uncompleted and not really convenient. Try the following instead that will work for single product pages and archives pages too (as shop page).

It handles any kind of product, including variable products and their variations.

For defined product categories, it replace the price and disable add to cart button on related products.

The code:

// Custom conditional function that check for specific product categoriesfunction check_for_defined_product_categories( $product_id ) {    // HERE your Product Categories where the product price need to be hidden.    $targeted_terms = array( '27419','27421' ); // Can be term names, slugs or Ids    return has_term( $targeted_terms, 'product_cat', $product_id );}// Custom function that replace the price by a textfunction product_price_replacement(){    return '<span style="color:red; font-size:12px;">' . sprintf( __( "Call our office %s for prices."), '<strong>516.695.3110</strong>' ) . '</span>';}// Replace price by a text (conditionally)add_filter( 'woocommerce_get_price_html', 'filter_get_price_html_callback', 10, 2 );function filter_get_price_html_callback( $price, $product ){    if( check_for_defined_product_categories( $product->get_id() ) ) {        $price = product_price_replacement();    }    return $price;}// Hide prices and availiability on product variations (conditionally)add_filter( 'woocommerce_available_variation', 'filter_available_variation_callback', 10, 3 ); // for Variationsfunction filter_available_variation_callback( $args, $product, $variation ) {    if( check_for_defined_product_categories( $product->get_id() ) ) {        $args['price_html'] = '';        $args['availability_html'] = '';    }    return $args;}// Disable add to cart button (conditionally)add_filter( 'woocommerce_variation_is_purchasable', 'woocommerce_is_purchasable_filter_callback', 10, 2 );add_filter('woocommerce_is_purchasable', 'woocommerce_is_purchasable_filter_callback', 10, 2 );function woocommerce_is_purchasable_filter_callback( $purchasable, $product ) {    $product_id = $product->get_parent_id() > 0 ? $product->get_parent_id() : $product->get_id();    if( check_for_defined_product_categories( $product_id ) ) {        $purchasable = false;    }    return $purchasable;}

Code goes in functions.php file of your active child theme (or active theme). Tested and work.