Suprema Astuta

If there is no app (in the app store) it will include as a generic zigbee device which only has on/off capabilities (like you already mentioned).
With Homey every brand/device needs its own app to get full functionality, that also means for this bulb.
So you could ask in the community app request topic If any community developer is willing to create an app for this brand, if you can’t do it yourself.
You could also ask Athom if they are willing, but they will need enough requests, otherwise they won’t put any energie in it.