[anonymously]

Discuss your concerns with the vet that is treating your dog, the diet recommendation may be temporary to assist in getting the urinary condition under control. A urinary blockage can be life threatening, in my opinion, that trumps growth issues.

I would comply with whatever the vet recommends, when the dog is stable you can make changes under the vet’s supervision.
BTW: Don’t expect to see immediate results…..it often takes 2-3 months to see any changes from diet and treatment.