Why not just wire a Relay Switch in with the Power Button.
Look at a Shelly Plus 1 Wi-Fi Switch
It can be configured as a Momentary Switch.
I REALLY like Shelly Devices as they are Wi-Fi, and have their own Shelly Cloud App that you can run independently of SmartThings.
Then there are Shelly Edge Drivers for it from @TAustin so you can fold them into your SmartThings setup if you want.
Looks like Aeotec has a new Pico Switch (Zigbee) , but it’s on pre-order. They used to have a have a Z-Wave Nano-Switch, but I’m not finding it on Amazon.