Best Team for Sayu in Genshin Impact
Team #1: Shinra Tensei (Ayaka 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.
Kokomi applies Hydro consistently enough to trigger Freeze and heals the team. If equipped with 4pc Ocean Hued Clam, she deals considerable damage as well.
Team #2: Xiao double Geo
Xiao's main source of DPS is his Anemo-converted Plunging Attacks. The Anemo conversion given by Xiao's Burst makes him lose HP continously, so a Xiao team requires healing and shielding. In this team, Xiao takes advantage of Zhongli's permanent shield and Geo resonance to increase his own damage.
Zhongli's role is to prevent Xiao's interruptions with his shield. Zhongli has the ability to keep his shield at 100% uptime and shred the enemies' resistances, as well as giving access to Geo resonance.
Albedo's purpose in this team to enable Geo resonance. He gives a notable contribution in DPS, but any Geo character actually works too, if not used elsewhere.