Much easier and better solution has been lately proposed to me by a fried of mine.
It’s the outcome of this thread where Devian sniffed Hue traffic
([Feature request]: Support Candle and Fireplace effects on Hue lights · Issue #15699 · Koenkk/zigbee2mqtt · GitHub).
Basically all you need to do is sent Zigbee command with the use of zha_toolkit (available via HACS: https://hacs.xyz/)
The command for candle would look like that:
service: zha_toolkit.zcl_cmd
data:
manf: 4107
ieee: light.philips_go_light
endpoint: 11
cluster: 0xfc03
dir: 0
cmd: 0x00
args:
- 0x21
- 0x00
- 0x01
- 0x01