I had a problem with this smart plug a few days ago,I took it apart and found out it has a ESP8266 12E inside. Can it be flashed with something else to work with HA and the power meter still work.
FYI, I followed this guide and successfully loaded ESP Home on a KMC Smart plug. The ESPHome YAMl is provided in this post. At the moment I have only done the one-relay version (using Relay 3 and deleting part of the YAML that references Relays 1 and 2), but will be trying on the 3-relay version soon.
Like @marcoby mentioned, you can pair KMC devices to Tuya smart app, then use Tuya integration.
I just did this, the only problem was Tuya app can’t discover my KMC smart tap automatically, I had to manually pair it. And all 3 outlets and energy monitoring are work.
I was having a similar problem with a rectangular smart socket, I was unable to add it via tuya/smart-life via the wifi/ble pairing mode. The problem was resolved after switching the pairing mode to Wifi-only.