I would strongly recommend taking a look to the app from AppDaemon, with just 4 lines of code, you connect the sensor with the light. I recently gave support to xy color lights, so it cycles through a list of colors. You can check which colors it goes through in here. Unfortunately, I do not have a video with the smoothness of the color changing, but I can assure you it is quite smooth since I use the transition attribute. I tested it with the same light you have, the LED1624G9. The configuration would look like this for you:
fireplace_light: module: z2m_ikea_controller class: E1810Controller sensor: sensor.fireplace_light_remote_action light: light.fireplace_light
If you need any help with the setup, let me know.