Hi Iga,
Is he eating and pooping normally? If he’s eating and pooping less then it’s possible he’s in pain. If it’s normal, then maybe you need to just bond with him more
The circling and honking is a mating behaviour, so it’s sensible that you neutered him. If you couldn’t touch him before either, it seems like you need to work on your relationship with him a bit
He would follow you before because of the urge to mate, but now that’s gone, he’s doing his own thing.
Also, note that some bunnies have a post neuter hormone surge, where they act out for the first month after the neuter as they deal with the changes.
To bond with your bunny, spend more time sat on the floor with him on his level, and hand feed him treats and food. Don’t try and pet him, just sit with him and let him come to you and realise you’re not scary. Gradually, you can start petting him and find out what he likes.