can't read a text file from an external storage through Kotlin

I am making a app to read a text file from an external storage through Kotlin. Even after adding permission tags and changing options in the manifest file, the following error is displayed and the text file cannot be imported. How can I solve this?

errCode:

java.lang.IllegalArgumentException: File content://com.android.externalstorage.documents/document/primary%3ADocuments%2Ftest.txt contains a path separator

kotlin File

class MainActivity : AppCompatActivity() {

    val getTextCode:Int = 2

    override fun onCreate(savedInstanceState: Bundle?) {
        val vBinding = ActivityMainBinding.inflate(layoutInflater)
        super.onCreate(savedInstanceState)
        setContentView(vBinding.root)

        vBinding.getFromTxt.setOnClickListener {
            val downUri = Uri.parse("/storage/self/primary/Documents")
            openFile(downUri)
        }
    }


    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)

        if (requestCode == getTextCode && resultCode == Activity.RESULT_OK) {
            try{
                data?.data?.also { uri ->
                    Toast.makeText(this, uri.toString(), Toast.LENGTH_SHORT).show()
                    Log.d("test", uri.toString())
                    openFileInput(uri.toString()).bufferedReader().useLines{ lines->
                        Log.d("test", lines.toString())
                    }
                }
            }catch(err:Exception){
                Log.d("test", err.toString())
            }
        }
    }

    private fun openFile(pickerInitialUri: Uri){
        val intent = Intent(Intent.ACTION_OPEN_DOCUMENT).apply {
            addCategory(Intent.CATEGORY_OPENABLE)
            type = "text/*"
            putExtra(DocumentsContract.EXTRA_INITIAL_URI, pickerInitialUri)
        }
        startActivityForResult(intent, getTextCode)
    }

}

manifest File

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.questionbank">

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.QuestionBank"
        android:requestLegacyExternalStorage="true"
        >
        <activity
            android:name=".EditActivity"
            android:exported="false" />
        <activity
            android:name=".TestActivity"
            android:exported="false" />
        <activity
            android:name=".PrintActivity"
            android:exported="false" />
        <activity
            android:name=".InputActivity"
            android:exported="false" />
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>



</manifest>