Prolly Razor, Rosaria, Fischl, and Mona/Barbara.
Rosaria is needed for the Superconduct reaction, which will increase Razor’s physical damage. She also can give some Crit buffs via her 2nd ascension passive, which also buffs Razor’s damage even further.
Meanwhile, Fischl acts as a sub-DPS, and also for the Electro resonance, which will give more energy orbs for the team, and ensures to keeps their bursts online all the time.
Lastly, Mona or Barbara is for support + Hydro applier, which is still in conjunction with either Electro and Cryo. Both characters works the same, so you just choose based on your needs (more damage = Mona, more support = Barbara).