Thermostat for heat pump

Hello everyone!
I have a samsung heat pump (air-water) installed. It heats or chill the water in inertia tank. I also have a firewood water boiler (fireplace) heating the inertia tank water in winter. It’s a double coil tank. The inertia tank send hot or cold water to daikin fancoils and heater elements for towels, and when it has hot water, send it to the hot water tank for baths, etc., and this tank is heated by water solar panel, heating element (disconnected for now) and inertia thank. I have thermostats starting circulation pumps and for that part (hot water tank) it works fine.
My problem is that I have the heat pump controlled by a radio thermostat that reads only the temperature of the room I have it. It’s an Elesta RTU300B, and it’s connected to the samsung heat pump thermostat (controlled by the Elesta one)
All works at 220v.
For now, the working mode is:

  • Heat pump or fireplace heat the inertia water

  • When water gets hot (50ºC), the fancoils circulation pump starts delivering hot water to them

  • Elesta thermostat reaches temperature setpoint and shuts down heat pump or water in fireplace gets cold, circulation pump from fireplace or heat pump turns off, and fancoils make the inertia water temperature drop, because they don’t stop.

  • Inertia themperature drops 10 to 15ºC until heat pump gets Elesta thermostat order to start or the water in fireplace boiler is got enough to start it circulation pump.

  • Elesta thermostat

  • Water pumps thermostat

  • Samsung thermostat

  • Elesta thermostat wiring

So, I have some issues:

  • The Elesta thermostat only allow hourly programming. And it only measures one room temperature.
  • The Elesta thermostat only sends turn on/off signals to heat pump.
  • Daikin fancoils work all time, even if their circuit circulation pump stops because of too low/high water temperature.
  • Daikin fancoils are split units, only controlled by IR remote, with only one on and one off schedule possible, and only hour based, but I’m working on them.

So, what I’m thinking is to replace the Elesta thermostat with something smart, with preference to ZigBee. And, if possible, using inertia tank temperature sensor values. I read somewhere that Shelly 1 can read wired temperature probes values, is that true? And using water temp does sense to me because I think the heat pump will work a little bit more time but with less energy consumption, just trying to maintain water temperature instead of trying to heat or chill the water as fancoils use it.
And I’m trying to controll fancoils with esphome (WeMos D1 mini by wire or IR), and if those don’t work, I’ll use some IR blaster. And I’ll have thermometer/hygrometer placed nearby to read temperatures to give setpoints to shutdown/start fancoils as needed.

My questions:

  • Am I thinking right?
  • What thermostat to replace the Elesta?
  • How to read inertia temperature?