Hi, I have only tried using joystick as mouse and improve that. While doing this I found one suggestion how to do what you are looking for here: https://www.reddit.com/r/olkb/comments/vgo39f/qmk_simple_question_is_it_possible_to_use/
You might find this interesting as well: https://github.com/qmk/qmk_firmware/blob/master/docs/feature_pointing_device.md#advanced-drag-scroll
BTW, are you creating custom keyboard (your own) or you just chosen something with joystick?
My current keyboard is 34 keys split, but I still need to move my right hand away from keyboard to mouse from time to time. I am aware about options that are possible (cirque trackpad, various trackballs and etc.), but I wanted to investigate what can be done with joystick (as it is quite cheap opti...
So I have tried to play around with joystick's algorithms a little bit and made QMK PR in the end.
Initially there was a difference for me, but now I can switch from one to another without a problem if I need to work on laptop keyboard for some reason.