Simple. The cube gets one shotted. The Borg Collective, which is linked across subspace, will notice a Cube suddenly going dark. They will send two spheres. The first gets one shotted, as the Death Star is simply too powerful to block its main weapon with adaptium shields. The second sphere beams over drones. The Death Star is assimilated. Resistance is futile. The Borg now have assimilated the technology of a planet killer weapon. Not that it matters. The Borg have the technology to wipe out entire star systems in one go. They choose not to, as that would go against the Identify, Adapt, Assimilate mindset. You can’t ascend other species into the Collective if you vaporise them all.
Simple. The cube gets one shotted. The Borg Collective, which is linked across subspace, will notice a Cube suddenly going dark. They will send two spheres. The first gets one shotted, as the Death Star is simply too powerful to block its main weapon with adaptium shields. The second sphere beams over drones. The Death Star is assimilated. Resistance is futile. The Borg now have assimilated the technology of a planet killer weapon. Not that it matters. The Borg have the technology to wipe out entire star systems in one go. They choose not to, as that would go against the Identify, Adapt, Assimilate mindset. You can’t ascend other species into the Collective if you vaporise them all.