I have the same view as @123 on this.
I have an AppDaemon app that smoothly increases brightness. This could probably be done with some kind of loop or some async code, but it’s not really a “clean” solution in my opinion. In addition if you want a smooth transition, there will be lots of commands sent to the device, which can lead to delays or missed commands depending on the device, network etc…
Fortunately, deconz (the software I use to integrate ZigBee devices like the Hue bulbs into Home Assistant) provides a method to smoothly increase/decrease brightness and to stop the dimming.
@jms3000 you may take a look at this app, I think it provides the colorloop you want.