Jetpack compose navigation with login screen

MainActivity.kt

package com.example.myapplication

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.Button
import androidx.compose.material3.Text
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.ui.Modifier
import androidx.lifecycle.compose.collectAsStateWithLifecycle
import androidx.lifecycle.lifecycleScope
import androidx.navigation.compose.NavHost
import androidx.navigation.compose.composable
import androidx.navigation.compose.rememberNavController
import com.example.myapplication.ui.theme.MyApplicationTheme
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.launch

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        val isAuth = MutableStateFlow(false)

        setContent {
            val _isAuth = isAuth.collectAsStateWithLifecycle()
            val navController = rememberNavController()
            val startDestination = if (_isAuth.value) "home" else "login"

            MyApplicationTheme {
                NavHost(navController = navController, startDestination = startDestination) {

                    composable("login") {
                        Button(onClick = { isAuth.value = true }) {
                            Text("Login")
                        }
                    }

                    composable("home") {
                        Column(modifier = Modifier.fillMaxSize()) {

                            Button(onClick = { isAuth.value = false }) {
                                Text("Logout")
                            }

                            Button(onClick = {
                                navController.navigate("profile")
                            }) {
                                Text("profile")
                            }
                        }
                    }

                    composable("profile") {
                        Button(onClick = { navController.navigateUp() }) {
                            Text("back")
                        }
                    }
                }
            }
            LaunchedEffect(this@MainActivity) {
                lifecycleScope.launch(Dispatchers.Main) {
                    isAuth.collect { isLoggedInState ->
                        if (!isLoggedInState) {
                            navController.navigate("login") {
                                popUpTo(0)
                            }
                        }
                    }
                }
            }
        }
    }
}