Unset variation attribute in WooCommerce https://wpsites.net/wordpress-tutorials/custom-functions-tutorials-small-plugins-for-woocommerce/

unset variation attribute.php

add_filter( 'woocommerce_available_variation', 'unset_variation_attribute', 10, 3 );
function unset_variation_attribute( $data, $product, $variation ) {
    // Define the attribute name you want to hide (e.g., "Size")
    $attribute_to_hide = 'Size';

    // Unset the attribute if it exists in the variation data
    if (isset($data['attributes']['attribute_' . sanitize_title($attribute_to_hide)])) {
        unset($data['attributes']['attribute_' . sanitize_title($attribute_to_hide)]);
    }

    return $data;
}