RuntimeException on plain NavigationDrawer

Question

I have an error going on my code. I am trying to build a navigation drawer to jump between fragments of my app. I modified the drawer to suit my need on the XML code. But after that, when i try to test the app, the app is installed but it crashes at launch. It shows this error :

java.lang.RuntimeException: Unable to start activity ComponentInfo{zeinfederico.example.tasklead/zeinfederico.example.tasklead.MainActivity}: java.lang.NullPointerException: findViewById(R.id.drawer_layout) must not be null
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3782)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3961)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:91)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:149)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:103)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2386)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:213)
        at android.app.ActivityThread.main(ActivityThread.java:8178)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:513)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1101)
     Caused by: java.lang.NullPointerException: findViewById(R.id.drawer_layout) must not be null
        at zeinfederico.example.tasklead.MainActivity.onCreate(MainActivity.kt:32)

I have a very hard time understanding why my drawer_layout could be null as it actually displays the drawer. To be sure, i tried to put a safe call operator. The problem is that the problem then jumps to NavigationView and so on. Often when i have this kind of behavior, i know that there is something downstream that isn't well written. But i couldn't find anything relevant here.

Since last update of android studio, i had a few weird errors. First, my bundle support became incompatible. I detail this issue in this question: Plugin "Android Bundle Support" is incompatible. And then, i got an exception in my android app analyzer. Maybe those issues are correlated with this one i don't know.

I would like to thank you in advance for your help and time on this issue of mine ;)

To help with this here is a copy of my MainActivity Code:

import android.os.Bundle
import android.view.Menu
import com.google.android.material.floatingactionbutton.FloatingActionButton
import com.google.android.material.snackbar.Snackbar
import com.google.android.material.navigation.NavigationView
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.navigateUp
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import androidx.drawerlayout.widget.DrawerLayout
import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.widget.Toolbar

class MainActivity : AppCompatActivity() {

    private lateinit var appBarConfiguration: AppBarConfiguration

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.content_main)
        val toolbar: Toolbar? = findViewById(R.id.toolbar)
        setSupportActionBar(toolbar)

//        val fab: FloatingActionButton = findViewById(R.id.fab)
//        fab.setOnClickListener { view ->
//            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
//                    .setAction("Action", null).show()
//        }
        val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
        val navView: NavigationView = findViewById(R.id.nav_view)
        val navController = findNavController(R.id.nav_host_fragment)
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        appBarConfiguration = AppBarConfiguration(setOf(
                R.id.nav_profile, R.id.nav_premium, R.id.nav_schedule, R.id.nav_schedule, R.id.nav_tutorial,
        R.id.nav_about, R.id.nav_settings, R.id.nav_procrastination), drawerLayout)
        setupActionBarWithNavController(navController, appBarConfiguration)
        navView.setupWithNavController(navController)
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        // Inflate the menu; this adds items to the action bar if it is present.
        menuInflater.inflate(R.menu.main, menu)
        return true
    }

    override fun onSupportNavigateUp(): Boolean {
        val navController = findNavController(R.id.nav_host_fragment)
        return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
    }
} ``` 

Here is content_main.xml:

    <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:showIn="@layout/app_bar_main">

    <fragment
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" />
</androidx.constraintlayout.widget.ConstraintLayout>