“or more likely we are an early civilization in the universe (according to Robin Hanson’s “Grabby Aliens” model) so, 2) quite possibly there are no grabby aliens populating the universe with S-Risks yet”
But our model implies that there are in fact many aliens out there right now. Just not in our backward light cone.
In our simulations, we find it overwhelmingly likely that any such spherical volume of an alien civ would be much larger than the full moon in the sky. So no need to study distant galaxies in fine detail; look for huge spheres in the sky.