Free Shipping Packages

Here is what I have using pure code no plugin but it is not correctly working after i impleted it. It works as in applies free shipping to threads once it reaches 25 or more but if in the future if i wanted to use a coupon of 20% off of products It doesnt seem to work for the other products that are not threads. Also another problem is that when i go to check out the item list is grey out with a loading spinning icon like it is trying to load but cannot because of my code snippet.

Can you take a look at it Please and point me in the right direction.

add_filter( 'woocommerce_cart_shipping_packages', 'threads_woocommerce_cart_shipping_packages' );

function threads_woocommerce_cart_shipping_packages( $packages ) {
    // Reset the packages
    $packages = array();
  
    // threads items
    $threads_items = array();
    $regular_items = array();
    
    // Sort threads from regular
    foreach ( WC()->cart->get_cart() as $item ) {
        if ( $item['data']->needs_shipping() ) {
            if ( $item['data']->get_shipping_class() == 'threads' ) {
                $threads_items[] = $item;
            } else {
                $regular_items[] = $item;
            }
        }
    }
    
  
  
      $threads_shipping   = array_sum( wp_list_pluck( $threads_items, 'line_total' ) );
	  echo $threads_shipping;
	  
	  if(($threads_shipping) > 25) {
		
		   $packages[] = array(
		  'ship_via' => array( 'free_shipping' ),
            'contents' => $threads_items,
            'contents_cost' => array_sum( wp_list_pluck( $threads_items, 'line_total' ) ),
            'applied_coupons' => WC()->cart->applied_coupons,
            'destination' => array(
                'country' => WC()->customer->get_shipping_country(),
                'state' => WC()->customer->get_shipping_state(),
                'postcode' => WC()->customer->get_shipping_postcode(),
                'city' => WC()->customer->get_shipping_city(),
                'address' => WC()->customer->get_shipping_address(),
                'address_2' => WC()->customer->get_shipping_address_2()
			  
			  
			  
            )
        );
		
        } else {
		
		 $packages[] = array(
		   'ship_via' => array( 'flat_rate' ),
            'contents' => $threads_items,
            'contents_cost' => array_sum( wp_list_pluck( $threads_items, 'line_total' ) ),
            'applied_coupons' => WC()->cart->applied_coupons,
            'destination' => array(
                'country' => WC()->customer->get_shipping_country(),
                'state' => WC()->customer->get_shipping_state(),
                'postcode' => WC()->customer->get_shipping_postcode(),
                'city' => WC()->customer->get_shipping_city(),
                'address' => WC()->customer->get_shipping_address(),
                'address_2' => WC()->customer->get_shipping_address_2()
			  
			  
			  
            )
        );
		
	  }
  
  
  
    if ( $regular_items ) {
        $packages[] = array(
		  	'ship_via' => array( 'flat_rate' ),
            'contents' => $regular_items,
            'contents_cost' => array_sum( wp_list_pluck( $regular_items, 'line_total' ) ),
            'applied_coupons' => WC()->cart->applied_coupons,
            'destination' => array(
                'country' => WC()->customer->get_shipping_country(),
                'state' => WC()->customer->get_shipping_state(),
                'postcode' => WC()->customer->get_shipping_postcode(),
                'city' => WC()->customer->get_shipping_city(),
                'address' => WC()->customer->get_shipping_address(),
                'address_2' => WC()->customer->get_shipping_address_2()
            )
        );
    }    
    
    return $packages;
}