I'm wondering if there is a way to see UI changes in an iOS application without having to restart the device or simulator. I know in react native since they use Javascript you're able to make a change to the background colour of a view and the background would reflect that change without having to restart the simulator. So I'm thinking since react native just converts javascript into native app code this might be possible in Native Development? Yes no maybe?
Doing normal native iOS development in the typical way -- no.
But, if you reproduce what ReactNative is doing (defining a data format for UI, loading it, and then wiring it up dynamically), then you can re-create it.
You might want to look into SwiftUI, which gives you a way to preview in Xcode without running the entire app.
Without that, if you use modules for all your UI code, you could incorporate a playground and see live changes as you code as well.