>>34121845The second one. They are only similar in the fact that both have "the power of light" (Z-power) and looks like they aren't native from any timeline's world like other beast are, looks like they are from the ultraspace itself, literally the space between dimensions/timeline
Still, Cosmog-Cosmoem-Solgaleo-Lunala is still just one pokemon that serves as a good prey for Necrozma.