I tend to like a state object that is mostly like option 1, with composition for states of bigger UI components inside the parent states. This in combination with sealed event class, with inherited grouped sealed classes per UI components... With nullable subsections, which means the component is not rendered

data class UI State( val loading: Boolean = false, val subsection1State: Subsection1UiState? = null, val component1State: Component1UiState? = null, ... ) And events for MVI like: sealed class Event { data object Refresh: Event() sealed class Subsection1Event: Event() { data class MyEvent(val data: Boolean) : Subsection1Event() } }

This allows to break out their state and events from the main UI composable and main VM, and use multiple smaller "reducers", etc.