I have the same problem, I'm using

val addEventToCalendarLauncher =
    rememberLauncherForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
        if (result.resultCode == Activity.RESULT_OK) {
            viewModel.onEventAddedToCalendar()
        } else {
            viewModel.onEventAddToCalendarFailed()
        }
    }

But same as you, I'm always getting resultCode = 0 and data = null