Screen capture in a single output

I am working in an embedded ARM device using a GStreamer & Qt application. I would like to capture the screen, which contains the camera input and some Qt widgets, to send that video stream to the GStreamer.

Using the drm backend I was able to setup a pipewire-output which enables an additional virtual screen, but what I would like to do is to have that pipewire output from the main screen, the same content is actually being displayed in the monitor. Is there a way to do this? Thanks