Open the Edit Emulators window in Tool and then pick your Demul emulator, then past the code into the AutoHotkey Script tab like this.
Yeah, I have a 1440p monitor as well so I use 2160, here is my full script for Demul.
Sleep, 3000
SetKeyDelay, -1, 110
MouseMove, 0, 2160, 0, R
$Esc::
{
Process, Close, {{{StartupEXE}}}
}
The one potential flaw with the mouse move AHK is that if you have something bump or move your mouse you could have the mouse cursor in the way again, the script just moves the mouse to the far bottom right corner off the screen where you don't see it.