Is there anything new about your kitten? Rabbits recognize things by smell so if the scent of the kitten has changed, that could be his cause for not taking to her as much as before.
There’s also the possibility his hormones are STILL there. It can take a month, sometimes a little longer for those dreadful hormones to go away. I also wonder – was this behavior something that started to happen before his neuter or only after? Sometimes change in behavior is cause for concern. It can signal an underlying health issue. If he’s not feeling well, that could definitely trigger some aggression or pushing you away on his part. If you believe this is a possibility, I think most vets will do an aftercheck (my vet did when my boy had been neutered and was showing signs of aggression) to make sure they A) got everything and B) to make sure nothing else negative came around because of the procedure. Extreme stress can bring out a number of different health issues and if the procedure was particularly stressful for him, it’s definitely a possibility something came out or surfaced that is causing him to feel off, kind of like how you feel off when you’re sick.
I had some particularly rambunctious teenager bunnies though. With my aggressive one, I turned to clicker training to help interact with my boy. It worked awesome although I don’t do it anymore with him. Ever since I interacted with him via clicker training his attitude got much better and we didn’t have a need for it anymore. It’s a great way to teach your rabbit tricks and is a very positive way to bond with them. Rabbits love mentally stimulating challenges. I would try it either way! You will surely be surprised at what your boy can do! 