Engulfing Lightning is the closest fit on the game's own numbers: Raiden Shogun's kit multiplies ATK, and a weapon is ranked here on whether its ascension stat and its passive act on that stat. Calamity Queller, Wavebreaker's Fin and Skyward Spine come next. No playtested ranking has been imported for Raiden Shogun, so this is arithmetic over the kit data rather than a damage measurement.
Run Thundering Fury on Raiden Shogun, with Celestial Gift and Silken Moon's Serenade behind it. Main stats are ATK% sands, ATK% goblet, ATK% circlet. Roll substats in the order Energy Recharge > ATK% > CRIT Rate > CRIT DMG.
Talent priority is Elemental Burst > Elemental Skill > Normal Attack. The Elemental Burst costs 90 energy, which is what an Energy Recharge target has to clear.
The strongest team is Raiden Shogun, Beidou, Kujou Sara and Bennett, built around Raiden Shogun: Electro · Mono Electro hypercarry.