How display two outputs from single camera?

Question

I followed this link to display a watermark during recording, and it worked. However, I want the watermark not to appear during the recording process but to be visible after the video has been saved. Here is the snippet to display a watermark during recording from the above link

private lateinit var captureRequestBuilder: CaptureRequest.Builder
private var captureSession: CameraCaptureSession? = null
private val captureSessionCallback = object : CameraCaptureSession.StateCallback() {
    override fun onConfigured(session: CameraCaptureSession) {
        if (cameraDevice == null) return
        captureSession = session
        captureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO)
        session.setRepeatingRequest(captureRequestBuilder.build(), null, null)

        btnStartStop.setOnClickListener(::startStopRecording)
        btnChangeCamera.setOnClickListener(::changeCamera)
    }

    override fun onConfigureFailed(session: CameraCaptureSession) = Unit
}
@Suppress("DEPRECATION")
private fun startPreview() {
    try {
        closePreviewSession()
        captureRequestBuilder =
            cameraDevice!!.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW)
        val surface = Surface(renderer.cameraSurfaceTexture)
        captureRequestBuilder.addTarget(surface) // <-- its possible add another target after this ?
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
            val config = SessionConfiguration(
                SessionConfiguration.SESSION_REGULAR,
                listOf(OutputConfiguration(surface)),
                Executors.newSingleThreadExecutor(),
                captureSessionCallback
            )
            cameraDevice?.createCaptureSession(config)
        } else {
            cameraDevice?.createCaptureSession(
                listOf(surface),
                captureSessionCallback,
                backgroundHandler
            )
        }

    } catch (e: CameraAccessException) {
        Log.e(TAG, e.toString())
    }
}

My goal is to display two outputs from one camera. With the command I used, I was able to display the camera on a surface. My question is, how can I add a second view placed on top of the first view so that the watermark is not visible during recording? or Are there any other approaches to adding a watermark during video saving?

note: I have tried using ffmpeg to overlay images, but the process is very slow and our users are not comfortable with it.