Woocommerce COD only for specific country with specific shipment rate

gistfile1.php

//enable COD only for italy
function payment_gateway_disable_country( $available_gateways ) {
  global $woocommerce;
  if ( isset( $available_gateways['cod'] ) && $woocommerce->customer->get_country() <> 'IT' ) {
    unset(  $available_gateways['cod'] );
  }
  
  //make COD the only available gateway for flat_rate shipping method (or other unused method)
  //you can use the label cash on delivery for flat_rate and determining the shipping cost for COD
  $chosen_methods = WC()->session->get( 'chosen_shipping_methods' );
  if ($chosen_methods[0] == 'flat_rate')
  {
    //only cod is available
    $available_gateways = array('cod' => $available_gateways['cod']);
  }
  return $available_gateways;
}
add_filter( 'woocommerce_available_payment_gateways', 'payment_gateway_disable_country' );

Hi, I need to make COD only available for one state in my country along with other gateways. And disable it for other states. What changes do I make here?