Also, the device description made sense to me. There is one switch of this type that community members have working well with SmartThings: the Leviton VRCS2. Two toggles in a single gang space. These are popular for bathrooms where one toggle is for the lights and one is for a simple exhaust fan.
That one is available in the US. I believe there’s something similar from Schneider for the UK that would combine with a dual micro relay, but I don’t know that one offhand. 