ARC optimized every mission.
In Gringotts, Harry used phase-sifting charms to bypass security, avoiding dragons and alarms. ARC destabilized the fidelity matrix of the vault, allowing Harry to extract the Cup and vaporize it with a modified Fiendfyre glyph.
In the cave, ARC redirected ocean tides and neutralized blood magic traps. The locket was melted on site.
The Diadem was found by reprogramming the Room of Requirement to reveal all lost items of significant magical weight. Harry stunned Draco, Crabbe, and Goyle with surgical precision and destroyed the Horcrux with a clean severing charm charged with light-energy.
"Three remaining Horcruxes purged. One soul fragment remains. Target: Voldemort himself. Secondary tether: Nagini."