Multiplying the rate if the any product in the cart falls under the specified categories.

functions.php

<?php

add_filter( 'woocommerce_package_rates','overwrite_shipping_cost', 100, 2 );
function overwrite_shipping_cost($rates, $package ) {
    global $woocommerce;

        if ( get_field( 'multiplier', 'option' ) ) :
            $multiplier = get_field( 'multiplier', 'option' );
        else :
            $multiplier = 1;
        endif;

        // My changes are starting here

        $product_category_id 		= array( 86, 21, 47 ); // Ids of Product Category
        $product_category_id_check 	= false; // Assuming that any of the product doesn't have above category
        foreach ( WC()->cart->get_cart() as $cart_item_key => $values ) { // looping through the cart.
            $_product = $values['data'];
            $product_cats_ids = wc_get_product_term_ids( $_product->get_id(), 'product_cat' ); // Getting category ids of the individual product
            
            foreach ( $product_category_id as $key => $value ) { 
	            if ( in_array( $value, $product_cats_ids ) ) { 
	                $product_category_id_check = true; // If any of the product in cart having category defined in $product_category_id variable then this will set to true. 
	            }
	        }
        }

        // My changes are ending here
        
        if ( ! is_admin() && $product_category_id_check ) {
            // If Shiptor 1
            if ( isset( $rates['shiptor-shiptor:14:delivery-point_shiptor_terminal'] )) {
                $rates['shiptor-shiptor:14:delivery-point_shiptor_terminal']->cost = $rates['shiptor-shiptor:14:delivery-point_shiptor_terminal']->cost * $multiplier;
            } 

            // If Shiptor 2
            if ( isset( $rates['shiptor-shiptor:14:to-door_shiptor_courier'] )) {
                $rates['shiptor-shiptor:14:to-door_shiptor_courier']->cost = $rates['shiptor-shiptor:14:to-door_shiptor_courier']->cost * $multiplier;
            }

            //If anothee shipping method
            if ( isset( $rates['rpaefw_post_calc:16'] )) {
                $rates['rpaefw_post_calc:16']->cost = $rates['rpaefw_post_calc:16']->cost * $multiplier;
            }
        }

    return $rates;
}

It works, thanks!
How can I contact you? Are you open for paid tasks?

It works, thanks!
How can I contact you? Are you open for paid tasks?

I am glad to know that it works for you. :)

Yep, I am open for paid tasks and you can contact me on below email address.
Email Address: parmarkartik19 at yahoo dot com