You should only choose a specific switch if you have exaclty the one it showed otherwise choose “others”. The Ikea shortcut button is visible at Phoscon App > Help > API information and also in the Phoscon App Beta:Phoscon App. You don’t need to install it separately, you can access Phoscon App and Phoscon App Beta variable.
I might have a follow up question: after getting the Shortcut-Button to work i only see „Single press“ and „long press“ in HomeKit (via homebridge). But when I use the event diagnostics the technically provided „Double press“ is recognized.
Same as i would use the Ikea gateway with the Shortcut Button for HomeKit.
So were is the gap and how do I get the „double press“ to work?
I believe it is a „Problem“ with the configuration and redirecting of the Button to HomeKit within phoscon, isn‘t it?