custom_shipping_methods.php

<?php
add_filter( 'woocommerce_available_shipping_methods', 'custom_shipping_methods' );
function custom_shipping_methods( $available_methods ) { 
    $carrier = 'ups';
    foreach ( WC()->cart->cart_contents AS $item ) { 
        if ( has_term( 'large-item', 'product_shipping_class', $item['product_id'] ) ) { 
            $carrier = 'usps';
            continue;
        }
    }
 
    $states = array( 'AK', 'HI' );
    if ( ! in_array( WC()->customer->get_state(), $states ) ) { 
        $available_methods = wp_filter_object_list( $available_methods, array( 'method_id' => $carrier ), 'NOT' );
    }
 
    return $available_methods;
}