I use an ISY hub (see
https://www.universal-devices.com/). For devices (e.g., switches), I use Insteon with that hub. I can control thermostats, three-way light switches, can turn on/off motion sensors, etc using Alexa. I can also set rules (not related to Alexa), like, if the garage door opens and it is after sunset, turn on the hallway light for 5 minutes. I can also tell Alexa a specific phrase, and she'll tell the hub to run my "out of town" program. Lights will then come on randomly, the thermostats will changes temperature to save energy, I'll get a text message if motion is detected in the house, etc.
That's the good news: you can do almost anything you can dream. The bad news: there is a learning curve (and replacing the three-way switches was a challenge, because you actually use two 2-way switches; the first switch controls the light and the second switch talks to the first switch). There is a really good forum for the ISY at
http://forum.universal-devices.com.