In my app I would like to generate backup files of database and shared preferences,this is the code to ask user permission to access external folders but dialog never appears

 private fun checkStoragePermissions() {
        if (ContextCompat.checkSelfPermission(
                this, android.Manifest.permission.READ_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED || ContextCompat.checkSelfPermission(this,
                android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED ) {
            if(!ActivityCompat.shouldShowRequestPermissionRationale(this,
                android.Manifest.permission.READ_EXTERNAL_STORAGE) ||ActivityCompat.shouldShowRequestPermissionRationale(this,
                    android.Manifest.permission.WRITE_EXTERNAL_STORAGE) ){
                requestPermissions(
                    arrayOf<String>(
                        android.Manifest.permission.READ_EXTERNAL_STORAGE,
                        android.Manifest.permission.WRITE_EXTERNAL_STORAGE
                    ), ALL_PERMISSION
                )
            }
        }
        else{
            if (executeBackup)
                backupFromDBData(WeakReference(this)).execute()
            else restore_data()
        }
    }

override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        when (requestCode) {
            ALL_PERMISSION -> if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                if (executeBackup)
                    backupFromDBData(WeakReference(this)).execute()
                else restore_data()
                return
            }
        }
    }

Manifest

`<uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
<uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE"
    tools:ignore="ScopedStorage" />

`

checkStoragePermissions It is called by clicking on a Button

I tried different libraries, even the one I use when starting the MainActivity asks for permission for Notifications but in this case nothing is ever requested