I think you can list input devices with
/dev/input/by-id to find out what inputs you have.
I would first check there (you can also probably just
ls -l /dev/input/js and then tab to see the numbers. you could then run jstest on the input and hit buttons on your pad to see if they are recognised (should change from off to on).
You’ll have to check the js inputs you have. I would start with that and see where they are and if any are recognised.