Sorry to hear that you got conflicting information. My BF Bas got the same story from a nurse, and he refused to neuter Breintje because he was too afraid to lose him. That nurse had been around for a long time, and in the past a spay/neuter was indeed more risky. But nowadays surgery and anaestethic techniques have improved. With a rabbit savvy vet and a young healthy rabbit there will hardly be any problems. Your rabbit will get a pre-op screening by the vet. If there are signs that your rabbit isn’t healthy enough for the operation the vet will address that situation first. I hope this will ease your worries.
And yes, as a rule, rabbits should always be spayed/neutered because it prevents serious health issues like certain cancers and it prevents behavioural issues (bad litter box habits, agression, etc). Breintje started to develop hormonal problems when he moved in with me. He turned into a completely different bunny: grumpy, spraying, humping everything in sight and being quite frustrated in general. We went to a rabbit savvy vet and it was fixed really quickly: we could take Breintje home the same afternoon and he made a quick recovery. We were very happy that we went through with the procedure. He has become so much happier and nicer to be around. I hope it’ll go just as smoothly for your bun!