Key of Khaj-Nisut is the closest fit on the game's own numbers: Kirara's kit multiplies HP, and a weapon is ranked here on whether its ascension stat and its passive act on that stat. Primordial Jade Cutter, Finale of the Deep and Splendor of Tranquil Waters come next. No playtested ranking has been imported for Kirara, so this is arithmetic over the kit data rather than a damage measurement.
Run Deepwood Memories on Kirara, with Vourukasha's Glow and Tenacity of the Millelith behind it. Main stats are HP% sands, HP% goblet, HP% circlet. Roll substats in the order Energy Recharge > HP% > 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 Kamisato Ayato, Nahida, Kuki Shinobu and Kirara, built around Kirara: Dendro · Hyperbloom.