I will confirm this for you.
I’m using two Honeywell Zwave 8320 thermostats. They integrate seamlessly with ST.
Alexa sees them both through the ST Alexa app.
I can fully control them via ST and smartass such as rule machine AND I can tell Alexa to adjust the temperature, and she does.
The only limitation I have found, and I think this is for all of them, is that Alexa does not adjust the temp properly when the thermostat is in auto mode. She also does not change the modes.
But I’m working around that.