Key of Khaj-Nisut is the closest fit on the game's own numbers: Dahlia'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 Dahlia, so this is arithmetic over the kit data rather than a damage measurement.
Run Heart of Depth on Dahlia, with Nymph's Dream and Vourukasha's Glow 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 Skirk, Dahlia, Furina and Escoffier, built around Dahlia: Hydro · Freeze.