How To Use World Wide Shipping Method With Multiple Zones https://wpsites.net/wordpress-tutorials/how-to-use-world-wide-shipping-method-with-multiple-zones/

world-wide-shipping-woocommerce.php

add_filter('woocommerce_package_rates', 'wpsites_remove_flat_rate_methods_over_150', 10, 2);
function wpsites_remove_flat_rate_methods_over_150($rates, $package) {

    $cart_total = WC()->cart->get_cart_contents_total();
    
    $threshold = 150;

    // Define the shipping method IDs to remove if cart total exceeds $150
    $methods_to_remove = array(
        'flat_rate:12',
        'flat_rate:13',
        'flat_rate:14'
    );

    // Check if the cart total exceeds the threshold
    if ($cart_total > $threshold) {
        // Loop through the rates and unset the ones to remove
        foreach ($rates as $rate_id => $rate) {
            if (in_array($rate_id, $methods_to_remove)) {
                unset($rates[$rate_id]);
            }
        }
    }

    return $rates;
}