Greyhounds are brilliant. So big but so gentle and calm. Good luck with your search

I find cavaliers to be quite placid. I own one and she is so chill and loves snuggles. Not overly smart, but pretty obedient usually. She does jump a bit but as they are a small breed, that might be less threatening. I think jumping is a thing a lot of dogs do until they are trained out of it.

The most chill dogs I’ve been around are beagles. But I’m sure all breeds can have a jumper in the mix

I think most dogs are excitable as pups and jumpy. Whatever you get make sure you take it to obedience lessons at an early age to train them not to jump. Smaller breeds are not as scary when they are coming at you .

Cabradoodles! I used to own a retail shop in an area where so many locals had them, my mother also has one and she was never a dog lover but his sweet nature and non-threatening aura sucked her in. I have Never met one who wasn’t well trained, friendly and open to a pat or cuddle.

I have personally never had a cavalier but I know a lot of people say how sweet and gentle they are!
Golden retrievers and labradors are highly rated family friendly pups aswell but the cavalier is smaller and so might be less intimidating!
Good luck with your child! I too was very nervous around dogs growing up and in some ways that’s a good thing. Dogs can bite and it’s good for kids to have some caution. Perhaps you can let her have a play date with a family friends pet which you know will be safe and gentle. All the best x