Hello,
Like I said before, the i.MX8QX is still under pre-production. I cannot guarantee if the software will work on your current board revision. However, to have a camera preview on the i.MX8MQ is as below:
gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw,width=1920,height=1080,framerate=30/1' ! queue ! waylandsink
This is for the i.MX8MQ, the gstreamer pipeline for the i.MX8QX may be different. I cannot assure you that the pipeline will work for the i.MX8QX. For more information, I suggest you go with your DBM.
I apologize for the inconveniences this may cause you.
Best regards,
Diego.