How to fix oculus quest 2 flat screen on build?

I think there is something wrong with your manifest...

Edit Project_Folder\Assets\Plugins\Android\AndroidManifest.xml
This is my file:

 <?xml version="1.0" encoding="utf-8" standalone="no"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" android:installLocation="auto">
   <application android:label="@string/app_name" android:icon="@mipmap/app_icon" android:allowBackup="false">
     <activity android:theme="@android:style/Theme.Black.NoTitleBar.Fullscreen" android:configChanges="locale|fontScale|keyboard|keyboardHidden|mcc|mnc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|touchscreen|uiMode" android:launchMode="singleTask" android:name="com.unity3d.player.UnityPlayerActivity" android:excludeFromRecents="true">
       <intent-filter>
         <action android:name="android.intent.action.MAIN" />
         <category android:name="android.intent.category.INFO" />
         <category android:name="android.intent.category.LAUNCHER" />
       </intent-filter>
       <meta-data android:name="com.oculus.vr.focusaware" android:value="true" />
     </activity>
     <meta-data android:name="unityplayer.SkipPermissionsDialog" android:value="false" />
     <meta-data android:name="com.samsung.android.vr.application.mode" android:value="vr_only" />
     <meta-data android:name="com.oculus.supportedDevices" android:value="quest|quest2" />
   </application>
   <uses-feature android:name="android.hardware.vr.headtracking" android:version="1" android:required="true" />
 </manifest>