Mastering Navigation 3: Managing Per-Screen ViewModels with NavBackStack

Navigation 3 in Jetpack Compose requires explicit setup to scope ViewModels per backstack entry. The key is using rememberViewModelStoreNavEntryDecorator() alongside rememberSaveableStateHolderNavEntryDecorator() in NavDisplay. This decorator leverages NavEntry.contentKey to uniquely identify each ViewModel instance, eliminating the need to manually supply unique key strings. For passing route arguments into ViewModels, both a standard ViewModelProvider.Factory pattern and Hilt Assisted Injection approach are covered with code examples. Forcing re-initialization when the same screen receives new data requires passing the key explicitly to the viewModel() call. A known limitation is that ViewModelStore does not currently support state retention when switching between multiple backstacks.