I seek near 100% overall system reliability. In order to detect problems, I need to detect the loss of online-status of all my smart devices, e.g. if a MQTT device is down, a ESPHome controller is not reachable, or if a battery status is critically low.
My internal solution is to monitor MQTT devices by its ‘lwt’-status, and to check ESPHome devices by a heartbeat mechanism. The ESPHome solution requires a switch on each ESP device: The switch is turned off perodically by an Home Assistant automation. A timer in ESPHome turns it back on. Monitoring the different sensors in an automation allows the creation of alarms, if something failes.
I would appreciate an unified approach made available. This would improve maintaining the overall system reliability.