[Disable gateway for certain country] #woo

disable-gateway-for-country.php

add_filter( 'woocommerce_available_payment_gateways', 'rudr_gateway_by_country' );

function rudr_gateway_by_country( $gateways ) {
	
	if( is_admin() ) {
		return $gateways;
	}
	
	if( is_wc_endpoint_url( 'order-pay' ) ) { // Pay for order page

		$order = wc_get_order( wc_get_order_id_by_order_key( $_GET[ 'key' ] ) );
		$country = $order->get_billing_country();

	} else { // Cart page

		$country = WC()->customer->get_billing_country();

	}

	if ( 'MC' === $country ) {
		if ( isset( $gateways[ 'paypal' ] ) ) {
			unset( $gateways[ 'paypal' ] );
		}
	}

	return $gateways;

}

//for multiple countries

f ( 'MC' === $country || 'MY' === $country ) {
	//unset gateway
}

//or

$countries = array( // array of unsupported countries
	'MC',
	'MY',
   // more countries here...
);

if( in_array( $country, $countries ) ) {
	//unset gateway
}