Our moon is officially called Moon. Luna is just something used occasionally, but not always. The sun is also officially named Sun. It’s just that those terms started being overloaded after we learned that there were other Moons and Suns. You can try to get all fancy with Sol and Luna, but those are just old Latin terms for Moon and Sun. They’re no less generic than the ones we currently use.

en.wikipedia.org/wiki/Moon#Names_and_etymology
en.wikipedia.org/wiki/Sun#Etymology