[cabmandone]

I just ordered an Amazon smart thermostat ($79) for the system in the media room/man cave out in my barn. I'll let you know what I think of it once I've got it installed. I don't have an alexa out there but I'll still be able to use the home, away feature to set the room back when I'm not out there. With an Alexa, it's supposed to set back if Alexa determines you're not home. Not sure how it does that.
Ecobee and Nest both utilize occupancy sensors. The Bryant Connex system control for my home has occupancy sensing that as I understand uses my phone to determine if I'm home or not.

Something else, Check to see if your power company offers any rebates for energy star thermostats. Mine offers up to $100 (can't exceed 50% of the cost) if I replace a standard stat with an energy star rated thermostat. So my $79 thermostat should end up costing me $39... good deal!