well why don't you list what issues you have on controller maybe people can help you fix them.
you say auto aim? do you mean aim assist?
you say the gun stops firing? probably more tike you stop holding the trigger or maybe you have set the gun to burst or semi auto mode
you say the sensitivity is bad but did you bother to watch one controller setup video?
have you even tried the several different options within the controller setup tab?
have you thought maybe your own controller might have issues?
I'm personally a KBM player, and believe me i had to go though the settings to get my mouse to feel good, i play with people who play on controller and so far I'm yet to here any of them complain about it.