Gest of the Mighty Wolf is the closest fit on the game's own numbers: Diluc's kit multiplies ATK, and a weapon is ranked here on whether its ascension stat and its passive act on that stat. A Teaspoon of Transcendence, Fruitful Hook and Redhorn Stonethresher come next. No playtested ranking has been imported for Diluc, so this is arithmetic over the kit data rather than a damage measurement.
Run Crimson Witch of Flames on Diluc, with A Day Carved From Rising Winds and Disenchantment in Deep Shadow behind it. Main stats are ATK% sands, Pyro DMG Bonus goblet, CRIT Rate / CRIT DMG circlet. Roll substats in the order CRIT Rate > CRIT DMG > ATK% > Energy Recharge.
Talent priority is Normal Attack > Elemental Skill > Elemental Burst. The Elemental Burst costs 40 energy, which is what an Energy Recharge target has to clear.
The strongest team is Diluc, Kamisato Ayaka, Venti and Diona, built around Diluc: Cryo · Melt.