Best Team for Xingqiu in Genshin Impact
Team #1: National
Chongyun provides Cryo infusion to the team and deals some damage on his own as well thanks to the Melt reaction and Bennett's ATK buff.
Team #2: Tazer
Team #3: Vaporize
Klee deals damage through her Normal, Charged attacks and her Burst, which are furtherly boosted by the Vaporize reaction. Klee's needs are a Vaporize enabler (in other words, a Hydro character that can work off-field) and a shield, as she's pretty squishy, downside of being a Catalyst user.
Bennett's utility consists in providing a huge ATK boost to the team as well as Pyro resonance. He can't really be replaced as his contribute is unique, but other Pyro support characters will at least grant the Pyro resonance.
Zhongli's role is to prevent Klee's interruptions with his shield. Any other shielder does the job too, but Zhongli has the ability to keep his shield at 100% uptime and shred the enemies' resistances.
Team #4: Freeze
Ayaka takes advantage from the Freeze reaction, Cryo resonance and 4pc Blizzard Strayer to gain 55% Crit Rate. She is the main damage dealer and her numbers get furtherly increased by Cryo swirl and her own passive talents. Note: Bosses can't be frozen, so this team is not effective against them.