Why was Vilya supposed to be the greatest elf ring?

[Voralphion]

that Elrond seems to be the weakest in personal power compared to Galadriel and Gandalf, so he was given the greatest ring in order to be on par with them.

Elrond wasn't given Vilya because he was the weakest, he was given Vilya because hje happened to be with Gil Galad when he died and passed on the ring. Also, Elrond although is never referred to as, is the only surviving descendant of Fingolfin and would therefore be the king of the Noldor in middle earth if they took someone as a king.