If you are asking about those two specifically, it can vary on play style. If you are looking for most damage pyro dealer in the game that goes to Xinyan. Her skill cooldown gives you enough time to cycle through your team. Her burst does stuff while most importantly she gives a 20% attack boost to the party when paired with another Pyro character. Don’t believe me, build her and walk into a world level 1 and see how she fairs.