A couple of things that jump out:
1.) You can try adding your switch as a Means to turn On in Room Lighting and see if that triggers things a little faster. It might save a step, which is really just a couple of milliseconds, but it might help.
2.) You might look at using Rule Machine to fade your lights down to 1 and then off. This would at least help with some of the ugliness since the color transitions would happen at level 1.
3.) With Circadian Daylight, you can use it to set a hub variable. From there, the hub variable can be used as the Color Temperature in Room Lighting. This way, Room Lighting will always turn on your bulbs at the correct temperature. You can then use Virtual Prestaging to take over. This is probably not necessary for your use case since you are using Zigbee bindings, but it is something that can help.
4.) With your Hue bulbs, I strongly recommend using [RELEASE] Philips Hue Zigbee Driver (not using Hue Bridge) as your driver. It supports prestaging both level and color/CT.
Personally, I use lutron and picos to control hue bulbs on the hue bridge. If Hubitat goes down, I can always use the app, Google Home, or Apple Home as long my internet and/or just power are still working. As you noted, Hue Scenes set the bulbs immediately to what I need.
