The controller support is unfinished and left in a functionally unusable state for years. All it needs to be useable is the implementation of the item radial menu that is used in the console versions. As it stands it is impossible to change weapons or items without either manually changing things in item menu in the slowest most clunky way possible or by using the keyboard thus negating the whole point of using a controller.
The obvious workaround is to use something like steam big picture mode. When i do i have noticed, in my system at least, using big picture mode in DayZ introduces micro stutter to horizontal camera panning. That camera stutter is not present when using DayZ in built controller support but it obviously introduces the problem of not being able to easily change items.
If you would just do 1 little thing it would make DayZ playable again for the first time in years. This used to be my favourite game and would love it to be again. PLEASE PLEASE PLEASE, Just finish what you started and include the radial item menu into the DayZ PC in built controller support.