This is a hypothetical more than anything, since I think we’ll all be dead and buried before somebody unironically runs the full Calvus or Elius set for PvP. This is assuming that you’re only running pieces from one set.
I want to say either the Ravenna Fallen King armor is definitively the best, because it gives three stats by default, although I don’t know if it’s higher or lower than some of the other boss sets.
i run kings set with cernyx amulet (although trying to swap out for sw helm and 2 agate because it gives ever so slightly more stats + jewel substats) solely for the purpose of getting as much stats as possible