The DeviceID is a consecutive number that comes from SDL. If you connect a device, it gets the DeviceID 0. If you disconnect and reconnect the device, it gets a 1 and so on.
I have added the ConnectionIndex. The order is decisive here. The first device gets a 0, the second a 1 and so on. If a device is disconnected and reconnected, it gets the next free number.
The mapping runs via the ConnectionIndex. Unfortunately, there is no unique serial number or anything like that for controllers.