Django searchfilter for multiple models

Using Django 3.2 with Restframework. Im trying for search filter and create a API with restframework which would output the searched term with its whole object.

I had a little success on that with official doc. But from that I can only search in a single Model and not as globally. I found a blog on how to use multiple Models together?

I tried for following from that:

<pre lang="Python">
class GlobalSearchList(generics.ListAPIView):
    serializer_class = GlobalSearchSerializer

    def get_queryset(self):
      query = self.request.query_params.get('query', None)
      users = MasterUser.objects.filter(Q(firstname__icontains=query) | Q(lastname__icontains=query) | Q(email__icontains=query) | Q(category__icontains=query))
      webinar = MasterWebinar.objects.filter(Q(host__icontains=query) | Q(title__icontains=query))
      section = ResourceSection.objects.filter(Q(resource_name__icontains=query))
      item = SectionItem.objects.filter(Q(item_title__icontains=query))
      all_results = list(chain(users,webinar,section,item))
      serialize_obj = serializers.serialize('json',all_results)
      print(serialize_obj)    #Json response is printed in console
      return JsonResponse(json.loads(serialize_obj), safe=False)   #nothing as output

<pre lang="Python">
class GlobalSearchSerializer(serializers.Serialize):
    
    def to_native(self, obj):
        if isinstance(obj, MasterIndividualMembers): 
            serializer = MasterIndividualMembersSerializer(obj)
        elif isinstance(obj, MasterUser):
            serializer = MasterUserSerializer(obj)
         elif isinstance(obj, MasterWebinar):
             serializer = MasterWebinarSerializer(obj)
         elif isinstance(obj, MasterResource):
             serializer = MasterResourceSerializer(obj)
         elif isinstance(obj, ResourceSection):
             serializer = ResourceSectionSerializer(obj)
         elif isinstance(obj, SectionItem):
             serializer = SectionItemSerializer(obj)

        else:
            raise Exception("Not found in any instance!")
        return serializer.data