A Thousand Floating Dreams is the closest fit on the game's own numbers: Ifa's kit multiplies Elemental Mastery, and a weapon is ranked here on whether its ascension stat and its passive act on that stat. Nightweaver's Looking Glass, Etherlight Spindlelute and Starcaller's Watch come next. No playtested ranking has been imported for Ifa, so this is arithmetic over the kit data rather than a damage measurement.
Run Desert Pavilion Chronicle on Ifa, with Viridescent Venerer and Song of Days Past behind it. Main stats are Elemental Mastery sands, Elemental Mastery goblet, Healing Bonus circlet. Roll substats in the order Energy Recharge > Elemental Mastery > CRIT Rate > CRIT DMG.
Talent priority is Elemental Burst > Elemental Skill > Normal Attack. The Elemental Burst costs 60 energy, which is what an Energy Recharge target has to clear.
The strongest team is Ifa, Ororon, Xingqiu and Sucrose, built around Ifa: Anemo · Electro-Charged.