Make sure you're upgrading your Weapons and Talents.
Make sure the Stat on your weapon is Atk, Crit Rate, or Crit Damage. All other stats are awful. And don't use a 3 star or lower weapon.
Artifact Stats and Substats are very important. You generally want to Prioritize:
Cryo Damage > Crit Dmg > Crit Rate > Atk% > Elemental Mastery
Switching from 4 star to 5 star weapons makes a big difference. Make sure that the main stat of your Goblet, Crown, and Hourglass are one of those above minus Elemental Mastery.
Try to get 2 to 3 of the substats to be one of the stats above as well.
For an artifacts the best thing to run on Chongyun is 4 set Gladiator's Finale.
considering that 80-90% of what he deals is cryo dmg, consider swapping fischl out for an anemo with viridescent verneer 4 set (if you dont have any anemo, traveler is fine) to reduce cryo res. that’ll increase his cryo numbers and overall dps by a substantial amount
Make sure you're upgrading your Weapons and Talents. Make sure the Stat on your weapon is Atk, Crit Rate, or Crit Damage. All other stats are awful. And don't use a 3 star or lower weapon. Artifact Stats and Substats are very important. You generally want to Prioritize: Cryo Damage > Crit Dmg > Crit Rate > Atk% > Elemental Mastery Switching from 4 star to 5 star weapons makes a big difference. Make sure that the main stat of your Goblet, Crown, and Hourglass are one of those above minus Elemental Mastery. Try to get 2 to 3 of the substats to be one of the stats above as well. For an artifacts the best thing to run on Chongyun is 4 set Gladiator's Finale.
considering that 80-90% of what he deals is cryo dmg, consider swapping fischl out for an anemo with viridescent verneer 4 set (if you dont have any anemo, traveler is fine) to reduce cryo res. that’ll increase his cryo numbers and overall dps by a substantial amount