Lots of JRTs have 'Queen Anne' legs. I've owned one & know several. Never had a problem with them. Come to think of it, my ex-husband had the same & he was fine too. You could always go to a different vet for a second opinion, but I think an operation if your pet is not suffering is extreme.
I adopted 2 dogs from the Dogs Trust in August 2019. I have just been to the vet to get Holly a chihuahua cross checked over as she has a luxating patella which we knew about before adopting. I also took Ivy a Jack Russell Cross to be weighed as they have both lost weight as they were both a bit round. The vet examined Ivy and told me that she will need an operation to correct her front legs that both turn out. It took me by surprise as she has been put on anti inflammatory medicine but she shows no sign of pain or lameness. I just wanted to know if anyone has had any experience of this. Surgery would be a referral to a specialist and I dread to think of the cost!