For a macOS app you don't need a simulator. For an iPhone app I've seen Claude Code launch the simulator without me needing to open Xcode.

I built an iOS simulator simulator, though only for RN. Runs in browser but covers 100% of the API of RN, iOS UI, and the top 1k native libraries basically now. Been an ongoing agentic experiment of mine that's about ready to release.

Kind of fun, you can develop iOS and Android both without a build step and without a Mac even.