WooCommerce - Hide free shipping if others methods exists

functions.php

<?php
/**
 * Hide free shipping if others methods exists.
 *
 * @param array $available_methods
 */
function custom_shipping_rules( $available_methods ) {

    if ( isset( $available_methods['PAC'] ) || isset( $available_methods['SEDEX'] ) ) {
        unset( $available_methods['free_shipping'] );
    }

    return $available_methods;
}

add_filter( 'woocommerce_available_shipping_methods', 'custom_shipping_rules', 10, 1 );