Thanks @Michael_Oborne. I appreciate your help.
Making a custom QGC like application is the link to my querry.
Quick summary:
I am trying to build a custom mission control application using QtAndroid(Qt5.15.0) and SDL(for controller) which as per our requirement needs to be deployed on herelink.
Also I have tried the Gamepad Tester application which is also not able to recognize the controller.
Can you please elaborate as to how SDL might be behaving and how can I get it to work or are there any settings I will have to do in the herelink to access the hardware.