We had a Carrier (Infinity) heat pump installed about ten months ago. Due to the significant limitations an Ecobee thermostat would have on the various functions of the system (five fan stages for instance) it was best for us to use the thermostat that Carrier provided. I have no complaints at all with it. I do, however, miss the remote wireless sensors I had with Ecobee.
We use a combination of SmartThings, Google Home, etc., for various things around the house (lights, water sensors, cameras, etc.,). Carrier must have an issue with Google because only Amazon Alexa will work with Carrier (outside of Carrier’s own MyInifnity app). Since Alexa works with ST couldn’t I grab some heat sensors and stick them in our kids’ rooms and just sync them to Alexa so Alexa can talk to Carrier? I’d be buying Alexa in part to communicate with Carrier. I’m not opposed to having both my Google Display (and Google home speaker and half dozen minis) and Alexa in the same room as long as they don’t start shooting each other.