There is only 1 smart thermostat that is made for RVs that I know of. Makers of the RV Soft Starts
Your average smart thermostat is not the right power type nor voltage to use in an RV without buying several components and doing some pretty screwy wiring.
I just installed the easytouch RV thermostat /u/Ethan0pia mentioned. I should have done it years ago. Installation is literally plug and play and the setup is dead simple. I found the scheduling feature to be way more useful than I thought it would be. It has an “away” mode that will let you select minimum and maximum temps. Really an awesome device.
EasyTouch_RV from Micro-air.com.
Has Bluetooth and Wi-Fi connection.
I replaced a Colman and it was plug compatible.
The feature I really like is the range setting. You can set the upper range for the air conditioner to enhance and the lower for the heater to engage so you never have to switch over.
Coleman-Mach has a new device called the SCC or smart control center. It will interface Coleman AC’s with pretty much any smart thermostat. You can also use it to control heat. It’s very new and not available everywhere. Message me and I can get you where I bought one