A few things need to be figured out before you decide on a dog or not.
Is your bunny comfortable with animals larger than it? Does your bunny get scared when it hears barking? Does your bunny get scared when it smells a dog (does your bunny get scared if it smells a dog on your hands that youve recently pet?). Is your bun comfortable sharing space with another animal? Is your bun comfortable losing space to another animal, if they dont get along? Are you comfortable with the possibilities that they will never get along and will need to be kept apart completely? Are you comfortable washing your hands every time you pet your dog, before spending time with your bun? Will you be able to split your time fairly between the both of them if they cannot be in contact with one another?
If your bun is afraid of dogs, and your dog and rabbit need to be housed completely apart, you still need to give your rabbit a few hours of attention per day. Which means, your dog will need to be ok without you around for a few hours out of each day. Likewise, your rabbit will lose out on the attention its normally getting. Thats not fair for either, but its doable if you can get into a routine and dont work long hour days. Also on working, your bun is still going to need 30 hours a week outside of its cage; this is around 4 hours a day. When your rabbit is out of its cage, your dog cannot be around it until it is properly trained in obedience, and only if your rabbit is not afraid of dogs. This would also be 4 hours out of each day you may not be able to spend with your dog, which again, isnt completely fair and isnt always doable if you choose a puppy over an adult dog.
But, you can spend less time with your rabbit and pen it instead of letting it free roam, if it has a bondmate as it will still be getting the needed amount of attention. Ideally, you would get your bunny a bondmate first. But again, if your rabbit(s) is/are afraid of dogs, you really should not get a dog. Buns can get very sick and even die from stress.