How can we overlay of an image using ionic native plugin

Am using the plugin Camera Preview

With following configuration
const cameraPreviewOpts: CameraPreviewOptions = {
x: 0,
y: 0,
width: window.screen.width,
height: window.screen.height,
camera: ‘rear’,
tapPhoto: true,
previewDrag: false,
toBack: true,
alpha: 1

Am unable to see the camera when toBack: true.
Am able to see the camera but overlay is not showing when toBack: false.

Please help me on this, i have spent so many days on this. It is the main functionality in our app.
Thanks in advance.

Note: I am using the angular project as ionic. (Firstly, it is the angular web project after that i have added ionic to this project for android and iPhone apps).

Ionic CLI version: 6.12.2