Not sure what you want to asynch load, but if you use asynch then you might not need a loading screen. Basically you open up your scene with the immediate gameplay or ui and then use asynch to load the rest.
As you can see, what is important here is your architecture and structure of execution flow. But it this is in fact what you want, you basically would put your loading screen in one scene and have the animation play. At the same time you asynch load the main scene in the background.
There are actions in the ecosystem to asynch load.
