I never use my built in controller for keyboard/mouse function because I have remapped everything through steam I use the default gaming controller setup but for the desktop the left joystick moves the mouse quickly right moves slowly I use the triggers for left and I right clicking as well as A and B. Shoulder buttons are forward backwards mouse double click is controll tab other is alt tab. Holding them down is alt F4 and control F4. Every button I have single click double click and holding down as another function. You get the idea

Point is would have to use a key mapping tool and that's perfectly fine adding buttons would of course have to use a remapper which is very simple and easy to do. You can ad extra keys to any keyboard and map it out however you would like to. What your referring to is having things automatically mapped out for you and not what I'm talking about.

      P.S. Sorry for the over explaining it. I take pain killers for a chronic pain issue and sometimes can't shut up. So I do apologize if I came off sounding like a dick. I respect your thoughts on this. I am looking for a flatter version of these 3 key keypad I could easily remap. Also I have tried remapping Bluetooth remote camera buttons and they work great other then the 1-2 second delay. 

https://www.amazon.com/gp/aw/d/B09TMVXNGG/ref=ox_sc_saved_image_2?smid=AJEXGJULMG4NA&psc=1