Add fake/virtual sensor to a Philips Hue Light

[LaUr3nTiU]

I've looked through Changing device properties of the HA integration, but I can't figure out a way to add a "power" sensor to https://www.zigbee2mqtt.io/devices/929002376201.html - it's a bulb that doesn't measure power consumption, but I want to simulate this by defaulting to 5W (or I can explore with doing it a % of 8W depending on the brightness).

I've tried modifying the configuration in the Add-ons -> Zigbee2MQTT -> Configurations -> Edit in YAML and also in the /homeassistant/zigbee2mqtt/devices.yaml via VS Code. The contents of these 2 files are different (this is confusing as well - as only the 2nd one seems to be updated when I make changes in the integration itself (like a entity rename)).

So, is there a way to make it expose a power sensor?

Also, the following code:

"0x001788010c67d998":
  friendly_name: light/office_philips
  icon: mdi:door

Does not make it use the "door" icon, as it keeps the "bulb" one. I've checked, and the icon is set as "empty" in MQTT in HA (as in, I didn't override it accidentally).