IMX462: how to increase sensitivity in low light conditions

Hello,

Where did you get the camera module(s)? Arducam
Model number of the product(s)? B0333
What hardware/platform were you working on? Raspberry Pi 4B
Instructions you have followed. (link/manual/etc.) Arducam documentation – Quickstart 
Problems you were having?

The camera is working on doing meteor detection during the night. The program uses a python script which uses under the hood gstreamer and the libcamerasrc plugin. Something like:

libcamerasrc ! video/x-raw,width=1280,height=720,framerate=25/1,format=UYVY   
                     ! appsink

Images are produced but the sensitivity to fine stars is too low in the current configuration. I would like to manually adapt the libcam configuration file to increase the gain or whatever. I am using a file called arducam-pivariety.json for that, which contains the settings from a similar imx290.json file provided or a new_imx290.json which I have seen posted in the forum. Is this OK? And if so, what fields and values would be recommended to set in order to increase the sensitivity?