It is preferred to use Chongyun as a Burst Nuke over Main DPS as his Normal Attack scalings are very low, even when including [C1]. His Burst on the other hand hits extremely hard on later constellations and takes a much higher total damage portion over his Normal Attack. On top of that, you can Reverse Melt all 3 hits of his Burst on enemies applied with strong Pyro, such as Bennett's Skill and Burst.
At [C2], his Skill reduces ability cooldown that is cast within the zone by 15%. This is one of the few abilities in the game that can reduce cooldown.
Chongyun's Burst is calculated as Claymore damage, which means it breaks Geo Structures / Shields at a much easier rate and can proc Shatter.
Viable Weapons with WIP Calculations:
Viable Artifact Set with WIP Calculations:
Regarding Weapon Choices:
Akuoumaru: At [R1], beats if Chongyun is used in a team with 260 or greater total team energy. only beats if [R2] and above otherwise.
Regarding Artifact Choices:
Sets
Noblesse Oblige (4): Chongyun is one of the best (4) holders since he has low energy requirements for his Burst.
Weapons
1Sacrificial Greatsword(4★) [R5]
2Wolf's Gravestone(5★)
3Favonius Greatsword(4★)
4Makhaira Aquamarine(4★)
Artifact Sets
1
Noblesse Oblige (4)
2
Scroll of the Hero of Cinder City (4)
3
Instructor (4)
Artifact Stats
Main Stats
SandsATK% / Energy Recharge
GobletCryo DMG
CircletCRIT Rate / CRIT DMG
Substats
1CRIT Rate / CRIT DMG
2ATK%
3Elemental Mastery
4Energy Recharge
Talents
1Burst
2Skill
Notes
Chongyun as an infusion support is rather niche, since it is only used to enable on-field Cryo characters that don't already have Cryo infusions. The most notable of these is Cryo DPS Freminet.
Chongyun's Infusion is overridden by Bennett's C6 and Diluc, but overrides Candace's infusion.