It doesn’t cover all possible cases. You are pointing to exierience during daylight, when you can afford initial light brightness. Imagine however how it will work during night. It will turn on to full brightness before being dimmed by adaptive lighting.
Adaptive lighting works with presumption that it must set light attributes as quickly as possible to minimize period when light has wrong brightness. Unfortunately it does that by executing turn on call everytime, instead if setting brightness/warmth. It’s because HA doesn’t provide light “change” service method. It’s known that turn on/off breaks transition in many devices.
TBH I experienced a few “flashes” during the nighttime and nobody convince me that it’s acceptable solution (sending light brightness after intercepting turn on event). It obviously works well with smart bulbs controlled through HA. But it has mentioned downsides in case of hardwired lights.
Anyway, In case of Shelly devices, I suggest to get output of adaptive lighting sensor/switch and send it to your device periodically using http calls or mqtt.
Shellies accept light attributes changes even if light is turned off. Thanks to that you will always turn on the light to expected brightness level / color.
If you decide to go this way, you can check out my attempt for adaptive/circadian lighting. It solves a lot of issues adaptive lighting component has providing fully configurable curves of intensity/warmth changes at the same time: Circadian/Adaptive Lighting NodeRed
I promised article above to @dbrunt. Some parts are still unfinished due to lack of time to finish the article. But main, bigger and most important one incl ready to use code is there.