What makes you think that thermostat is going to fail? It's about as simple a device as you can imagine and doesn't really have any parts that wear out.
Do you really need a smart thermostat, or just something programmable? A programmable thermostat works for most people, unless you have schedules that vary wildly week to week you probably won't see much if any benefit from a "smart" stat.
We have a Honeywell panel in my shop with wireless. I have an app on my phone that can check the system status, arm / disarm / bypass sensors and things like that. I get notified via the app when the alarm is set or unset as well as if it goes off or if there's any faults.
Wireless range is very good (alarm systems use a different technology than WiFi which can penetrate buildings a lot better). Can add lots of sensors either wired or wireless - we have multiple PIR sensors plus door switches and a panic button mounted under the front desk.
Sensor batteries have been lasting about 3 years. They take a CR123 lithium battery that's easy to change.
Ours was installed via a local alarm company.