Woocommerce Disable/Enable Shipping Methods based on the number of products in the cart

wcsmboq.php

// Disable/Enable Shipping Methods based on the number of products in the cart by u/acephaliax

add_filter( 'woocommerce_package_rates', 'conditionally_enable_shipping_methods', 10, 2 );

function conditionally_enable_shipping_methods( $rates, $package ) {
    $cart_items_count = WC()->cart->get_cart_contents_count();

    // Instance IDs to adjust (replace with your actual IDs)
    $method_id_to_disable_for_large_carts = 9;
    $method_id_to_enable_for_large_carts = 10;

    //Set cart item quantity to trigger rule
    if ( $cart_items_count > 2 ) {
        // Disable method 9 and enable method 10
        foreach ( $rates as $rate_key => $rate ) {
            if ( $rate->get_instance_id() == $method_id_to_disable_for_large_carts ) {
                unset( $rates[$rate_key] );
            } elseif ( $rate->get_instance_id() == $method_id_to_enable_for_large_carts ) {
                $rate->enabled = true;
            }
        }
    } else {
        // Disable method 10 and enable method 9
        foreach ( $rates as $rate_key => $rate ) {
            if ( $rate->get_instance_id() == $method_id_to_disable_for_large_carts ) {
                $rate->enabled = true;
            } elseif ( $rate->get_instance_id() == $method_id_to_enable_for_large_carts ) {
                unset( $rates[$rate_key] );
            }
        }
    }

    return $rates;
}

To find shipping instance ID go into the shipping zone and hower over the shipping method edit link, give it a sec and the full url should pop up on your broswer. Alternatively just click through and it will be i thr url.

Solution for : https://www.reddit.com/r/woocommerce/s/bhBYXkIYRi