Hi,
I just understood your need.
Actually, this is not necessarily related to MQTT, but first of all, having an actuator on the dashboard for brightness and light.
So, I think your need is related to the request Gestion de la couleur des ampoules RGB depuis le dashboard
We are in the same theme, we are even completing the need.
In this case, I will not ask you to provide development, because this dashboard presentation topic is a topic that is starting to date. We had already addressed the subject, some had even provided graphic proposals.
So, if you have some design notions, you can propose a nice integration of these controls in the dashboard.
@pierre-gilles no choice has been made yet on the presentation of the light color controls? (colors / brightness / …)