I don’t want to take this thread off topic, but there is an existing zigbee option which works with smartthings and will control both lights and fan speed in a single gang controller format. 
See the community FAQ on Fan Control options. It mentions echo in the thread title, but it covers all the options. The thread title is a clickable link:
FAQ: 2018 Ceiling Fan and Dimmer light wall mount control compatible with SmartThings and Alexa?
Hopefully we’ll be able to add the inovelli fan controls to that FAQ soon, but we don’t include pre-release devices.