https://wabbitwiki.com/wiki/Spaying_and_neutering_rabbits#Before_the_operation

Above are some things to keep in mind before the operation. In terms of things to do to make things as least stressful as possible, I actually suggest simply doing as you usually would– rabbits pick up on routine easily, so sticking as close to that as you can may be good. She is going to be stressed regardless since you will likely just be dropping her off at the vet and not pick her up until later that day, so she will be naturally stressed at the vet. As long as you have chosen a rabbit-experienced exotic vet to do the operation, I would trust their expertise in managing anesthesia and pre- and immediate post-op care well.

I just wanted to add that inhalation anesthesia is the most common choice of anesthesia when spaying a healthy young rabbit. Many vets also place a canula in the ear for easy access.

If she likes banana, a small piece of banana would be good. Fresh herbs are good too prior to surgery, they have a calming scent. You can put some in the carrier for the transport – she might not eat in the carrier, but the scent will be there. Send a little lunch box with her so the staff can offer yummy things to her as soon as she wakes up. Have some banana and herbs ready for her when she comes home.