GStreamer doesn't release camera

Hi,
Please share information of the camera for reference:

$ v4l2-ctl -d /dev/video0 --list-formats-ext

And do you have other USB cameras for a try? See if it it specific to the camera. You may follow the steps in:
Jetson Nano FAQ
Q: I have a USB camera. How can I launch it on Jetson Nano?