I created a Wifi controlled gas fireplace using a Wemos D1 Mini and a relay. As expected, the actual ESP part of the project is fairly easy. The harder part is getting power underneath your fireplace if you don't already have it. If you do have it, and you have a gas fireplace that is currently controlled with a switch, this is a nice simple project that doesn't take much effort.
It also features web based OTA firmware updates. And it automatically turns the fireplace off after X minutes(easily changed in the code). And if you have Home Assistant, you can easily integrate it in there with MQTT and make a nice addition for setting up some scenes and even link it up with HomeKit.
I tried to make it easy for a beginner to be able to understand with pictures and commented code. But if there's anything that doesn't make sense, feel free to ask.