We have a member called Niamian who got a german shepherd-mix puppy when she already had two buns. She’s been inactive for a while, but she just recently returned. You could try PM-ing her and ask her to this thread, she might have some tips for you.
I have a dog and a bun, but the dog was 3 years old when the bun came, so my situation was very different.
In any event, always make sure there are safe hiding-places for the bun. If sth happens, if they accidentally come loose together, the bun MUST have a place to run to where the dog can’t reach it. Under a dresser or sofa or something, where the dog absolutely can’t get in under even if it were to try. A bun can still be scared to death by a dog, but some rabbits are quite resilient to scares, so ensuring that the bun can get out of the dog’s physical reach is really important.
What type of dog are you thinking about getting? Some breeds are more difficult to train than others.