[Magda]

It’s only my opinion but I would keep him intact and train out the undesired behaviour.

He is starting to become an adolescent dog and he will be more “stubborn” neutered or not and it’s something you will have to work through. Puppies start to become independent at that age, they like to explore and realise that there are other things which are rewarding apart from you. Make sure you are still the most interesting and rewarding thing in their world. Have a lot of structure, give a reward and consequence for his actions.