Toolbar automatically showing back arrow when created

I have created a MainActivity where I have a DrawerLayout

XML File

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/drawer_layout"
    android:fitsSystemWindows="true"
    xmlns:tools="http://schemas.android.com/tools">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <androidx.appcompat.widget.Toolbar
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="@color/gray_95"
            android:id="@+id/toolbar"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
            android:elevation="4dp">

            <EditText
                android:layout_width="150dp"
                android:layout_height="wrap_content"
                    android:hint="My toolbar"
                android:textColor="@color/white"></EditText>

        </androidx.appcompat.widget.Toolbar>

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">



		// ALL MY  MAIN ACTIVITY XML




         </RelativeLayout>
    </LinearLayout>


    <!-- Navigation View -->
    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        app:menu="@menu/drawer_menu"
        android:layout_gravity="start"
        android:background="@color/gray_95"
        app:itemTextColor="@color/white"
        app:itemIconTint="@color/white"
        app:headerLayout="@layout/drawer_menu_header"/>

</androidx.drawerlayout.widget.DrawerLayout>

On this Activity I have created the basic code that is required to making work the Drawer which is called when from onCreate(Bundle savedInstanceState) and overrided onNavigationItemSelected(@NonNull MenuItem item)

JAVA

  private void setDrawerLayout() {
    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayShowTitleEnabled(false);

    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    NavigationView navigationView = findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);

    ActionBarDrawerToggle mToggle = new ActionBarDrawerToggle(this, mDrawerLayout , toolbar, R.string.open_drawer, R.string.close_drawer);
    mToggle.syncState();
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    mDrawerLayout.addDrawerListener(mToggle);
}

The Navigation works, but I am dealing with an error. As the previous XML file shows, I have added the whole Activity under the Toolbar. I am assuming that what I am doing wrong is that instead of the activity, I should create a Fragment and add the following lines of code to onCreate method:

            getSupportFragmentManager().beginTransaction().replace(R.id.MYMAINFRAGMENT, new SettingFragment()).commit();

but before doing that, I wanted to confirm if this is the issue or not, since it would make me to spend a lot of time on it (the project is advanced, and I would need to make tons of changes)

I attach a picture to show the current solution

As you can see, as soon as I launch the application the back button is shown. When I click on it, it simply opens the drawer. What could be happening? Do I need to create a MAINFRAGMENT?

Remove this line:

   getSupportActionBar().setDisplayHomeAsUpEnabled(true);