Yelan build recommendations

Yelan is an off-field DPS who is able to apply Hydro off-field via her Elemental Burst, this part of her kit acts similarly to Xingqiu's Elemental Burst. Yelan mainly scales off HP%, so don't build her with ATK%. Yelan also wants a lot of Energy Recharge to be able to maintain her Elemental Burst uptime (up to ~250 ER), this can decrease depending on the number of Hydro units or energy providers in the team.

Regarding Weapon Choices

Elegy for the End
This weapon is to be used only in reaction based comps such as Vape Hu Tao, Yelan's personal damage is lower than other options on this list, but is more beneficial for the team's damage per rotation.

Mouun's Moon
This weapon works best at [R3]+ and makes HP% Goblet potentially a stronger option instead of Hydro Bonus especially in comps with strong DMG% buffs.

Sacrifricial Bow
This ideally needs to be at refinement [R3-R5] to function properly in most Yelan teams rotations without desyncing the rotation and extending her field time.

Aqua Simulacra
Can still perform well at high Energy Recharge as long as your minimum requirements are met.

Hunter's Path / Polar Star / Thundering Pulse
They are usable on Yelan, but she doesn't take full advantage of them. It is recommended to use them on characters who benefit more from their passives.

Regarding Artifact Main Stats

Goblet
HP% Goblet is to be used only if the Hydro DMG% option has terrible substats and HP% option has great substats, or if Yelan has strong DMG% buffs such as Emblem of Severed Fate (4) + Mouun's Moon (especially with refinements) or Raiden + Kazuha and so on.

On top of that it's never recommended to run more than 2 HP mainstat artifacts at a time.

Regarding Talent Priority

Normal Attacks
Level this up only if you want to constantly use her Breakthrough Barbs.

Big thanks to Vladone ツ#9281 and jstern25#1399 from Yelan Mains for helping us with the calculations.