I've found LLMs are extremely hit or miss with iOS development. I think part of that might be how quickly Swift and SwiftUI is changing coupled with how bad Apple documentation is. I have loved using them to generate quick views and such for scaffolding purposes and quick iterations, but they tend to break down quickly around asynchronous coding and non-trivial business logic. I will say they're still incredibly useful to point you in a direction, but can be very misleading and send you down a hallucination rabbit hole easily.