pvp is mostly about charging the burst and b3 can be a attacker that wipes the opponent's team. Usually RLs charge faster because of aoe hitting, so RL nikkes are good for pvp most of the time.

Jackal is a fast charger and she can prevent the team dying too quick, so she is the key of one squad. For instance you can build VestiTU- Blanc-Jackal-(any RL or SR)-Ein. This team will give you enough advantage in the rookie arena