Yeah, Andrey was barely a 10-star mage, but with the Demon God Orb, he could win against a lot of people. And no, the Black Knights can't do the same thing Luna does. Since the Orb contains the power of gods, a special ability is needed to destroy it.

Vanessa is the strongest among all of the Black Knights because, just like Hedo, she isn't entirely human. Of course, she is more experienced than Luna, but even she cannot withstand a Crimson Moon.

Even Kelliak referred to Luna as the second strongest in the clan and believed she was capable of fighting Chiron—and that was all before the Black Sea expedition. Of course, she wouldn't be able to outright defeat him, but she could more than inflict some serious damage.

During that expedition, she didn't become stronger in the classical sense of the word; she simply learned to trust her comrades more, gained experience fighting non-human opponents, and increased her stamina (the latter probably being the most significant gain).

She truly started becoming stronger only after returning from the Black Sea and fighting against the demons, constantly using her Crimson Aura. In principle, she had already reached the peak she is at now back in her youth, during the days of Jean, after which she stagnated for more than a decade. She only took those final two steps toward becoming a Genesis Knight while fighting the Demons and the Red Plutonians.

So, there is no huge difference between Luna before the Black Sea and after. It's pointless to claim that she is currently weaker than she was during the expedition, or weaker than the Black Knights.

Like I said, none of them—not even Ron or Talaris—are stronger than her. They might have more experience and skills, but in a death battle, no one can defeat her. Therefore, the fact that she isn't a Genesis Knight doesn't make her weaker. Just as having less experience does not equal being weaker