NiELkE So I tried using a controller. I see what's happening. When you move the mouse of keyboard, it'll switch. But when you use the controller, it'll switch back. So even if you macro inputs with the keyboard, as soon as you press a button or move the stick on the controller it'll cut off the keyboard functions. Interesting.
So this is annoying. But it can be done. AHK, can do controller inputs. But not sure if it'll do emulated. So it depends on your controller type. If you are using a non-XBox controller, the buttons are being emulated. Within the program that is emulating the inputs, you should be able to set profiles. Make a profile for that character. Then you just make a macro to hold the button down or set it to a toggle. I'm guessing it just needs to think that it's being held down and it's not actual auto cast on a timer. It's being cast because it's held down and cooldown resets.
It's definitely easier if the actions are saved to the controller and the controller is the one doing it. Like controllers with a built in turbo mode. It's just using the right program that intermediates.
I know it's possible, because for D2R, I mainly use M+KB. But for drops in public games, I'd switch to controller because I had the pick up key set to "turbo" which would rapid press. It would pick up items before they even hit the ground. It's just changing that to toggle and not repeat.