I use a lot of ESP8266 for my smart home.
Some with ESPurna, some with Tasmota, a couple with ESPEasy.
An important feature of them is that they don’t have hard coded settings for MQTT server or wifi authentication, but they let you browse SSID in AP mode, then the board reboot and it connects to the network.
This way, I can even provide one or more fallback networks.
This is for MQTT too: I can easily swap MQTT server, without recompiling the .ino.
Can’t this be done for OpenMQTT Gateway? Having settins on board is very important for user experience.