What about this?

fun <T, R> StateFlow<T>.mapStateIn(
    scope: CoroutineScope,
    block: (T) -> R,
): StateFlow<R> {
    val started: SharingStarted = SharingStarted.Eagerly
    return drop(1).map { block(it) }
        .stateIn(scope, started, block(value))
}