fix: several bug fixes as found in logs

src/Form/DestinationType.php

@@ -69,7 +69,7 @@ class DestinationType extends AbstractType
 
         if (null !== $hotelBusProId) {
             $hotel = $this->hotelDataProvider->get((int) $hotelBusProId);
-            $hotelLabel = sprintf('%s (%s)', $hotel->getName(), $hotel->getCode());
+            $hotelLabel = null !== $hotel ? sprintf('%s (%s)', $hotel->getName(), $hotel->getCode()) : 'unbekannt';
         }
 
         $form