Ganyu is, in a way, a very easy and forgiving character to build when it comes to his artifacts. Because she is a Cryo character, you can easily create Cryo Resonance with your party composition. This will help compensate for the critical rate shortfall. So when choosing artifacts or weapons for her, you can focus all of your attention on giving her Crit DMG instead. This is perfect because most of his damage comes from critical hits.
Some artifacts you can consider for your Ganyu build are:
Loser Blizzard 4 pieces
The Blizzard Strayer Full Game is the best game you can put on your Ganyu. It doesn’t matter if you run it as a main DPS or a sub-DPS. The 4 piece effect increases your crit rate against enemies affected by Cryo. There is an additional boost if enemies are frozen, which means a 4-piece set can give Ganyu a 40% critical boost. Since all of Ganyu’s damage potential comes from his Cryo attacks, enemies will always have Cryo on them. So you can focus your attention on your Crit DMG instead to maximize the amount of damage you deal on critical hits.
4 CP The Reminiscence of Shimenawa
Ganyu’s Elemental Burst grants a 20% cryo buff to anyone in her circle (ascension passive), which also applies to her. A 4-piece Reminiscence of Shimenawa asks you to sacrifice this boost in favor of increasing the set’s 50% DMG. Obviously, you’ll want to take 50% of the 20%! Each time you use your elemental skill, your energy decreases. But your charged attack will do much more damage. It’s a perfect swap as Ganyu’s Burst isn’t his main source of damage anyway.
2 CP Noblesse + 2 CP Blizzard Strayer O 2 CP Noblesse + 2 CP EM
If you’re building your Ganyu as a sub-DPS in a Melt or Freeze comp, you’ll likely put EM weapons in there. If you do, your artifacts can be focused on increasing your burst and cryo damage. Her Burst will be the main source of Cryo application in a Reaction group, and you can also focus on her Cryo DMG base if she needs to land attacks herself. For reference, until I collected the 4 pieces of Blizzard Strayer for Ganyu, she had Noblesse + Blizzard Strayer. Even though she was a primary DPS, she was still incredibly powerful.
Genshin Impact is available for PS4, PS5, Windows PC and mobile devices. You can only lure Ganyu into Genshin Impact during Adrift in the Harbor Character Event Wish.