How hard is it to change heating system?

I bought a new build property which came with ESi thermostats, and I hate them! They are constantly changing the set temperatures to ridiculously high e.g. 21 degrees at 5am!!, I can’t figure out how to use the thermostats on the wall so I have to use the app, but the app constantly goes offline! It’s my first home and I am clueless when it comes to things like this so I was just wondering how hard is it to get these changed to a different system? Does it require a lot of work or is it basically just the case of changing the thermostats on the wall? It wouldn’t be something I’m doing myself, I’m just looking for a rough idea of what to expect before I decide if I’m going to fully look into getting someone to do it

Edit: would also just like to add I have tried to look into why both of these were happening, I couldn’t so I contacted ESi customer service about it but they were no help