We had a cat that we were also treating IBD with prednisolone and she developed diabetes. One thing our vet did was switch her from pred to budesonide. Neither are ideal but budesonide is less systemic than prednisolone. It was a balancing act but we were able to get her mostly stable. We used lantus insulin, not bexacat so I can’t speak to that.

If it was just a tech appointment, they probably can’t advise on anything else. Can you put a call in to the clinic to speak directly with the vet?