It doesn’t matter whether it’s good or not, it’s okay. There are so many vassal states in the Shang and Zhou dynasties, you can just choose a name among them. Even Qin and Tang can be named Southern Qin, Northern Qin, Eastern Tang, Western Tang and so on.
But I think there are three principles: first, it should be loud and loud; second, it should not use unusual words; third, it should not be too literary.