точно всё исправил

server/proj/audio/serializers.py

@@ -7,17 +7,15 @@ class SongSerializer(serializers.ModelSerializer):
         fields = ('id', 'unique_id', 'azura_id', 'title', 'artist', 'album', 'genre', 'art')
 
 class FavoriteSongSerializer(serializers.ModelSerializer):
-    song = serializers.SerializerMethodField()
+    
     class Meta:
         model = FavoriteSong    
         fields = ('id', 'song', 'user')
 
-    def get_song(self, favorite_song):
-        song = Song.objects.get(id=favorite_song.song_id)
-        return SongSerializer(song, many=True).data
-    """ def to_representation(self, instance):
+    
+    def to_representation(self, instance):
         rep = super().to_representation(instance)
         rep["song"] = SongSerializer(
             instance.song).data
-        return rep """
+        return rep 
         

server/proj/audio/views.py

@@ -19,8 +19,9 @@ class SongViewSet(ViewSet):
     }
     def list(self, request):
         user_pk = request.user.pk
-        queryset = get_list_or_404(FavoriteSong, user=user_pk)
-        serializer = FavoriteSongSerializer(queryset, many=True)
+        songs_pk = [i.pk for i in get_list_or_404(FavoriteSong, user=user_pk)]
+        queryset = Song.objects.filter(id__in = songs_pk)
+        serializer = SongSerializer(queryset, many=True)
         return Response(serializer.data)
     
     def retrieve(self, request, pk=None):