Freeze Ganyu with Kazuha Diona Mona
Rare Possum
C0
Ganyu
R5
C0
Kaedehara Kazuha
R3
C6
Diona
R3
C0
Mona
R3
Rotation 17.5s
The rotation is fast enough that Ganyu is able to snapshot her own A4 Cryo Damage Bonus onto her Burst second rotation onwards. Kazuha then provides grouping to allow Ganyu to abuse her quadratic scaling while Mona holds them in place with Freeze and buffs via her Omen. Diona generates particles for Mona.
The timing for the A4 is quite tight, so it is important to learn the rotation quickly. This is harder on high ping.
Because of the reduced rotation time, Ganyu's energy requirements are increased significantly. This means the rest of the party must be on energy weapons like favonius weapons to generate energy for her. Sacrificial warbow is an option for Diona at R5, and it will reduce energy more than favonius, but the rotation is already quite tight as is.
Rotation:
Ganyu CA
Kazuha tEP Q
Diona hE
Ganyu EQ
Kazuha hEP
Mona QN1E
Ganyu CA