Solar Flare Drill

The four Luminite drills are one tool wearing four costumes, so take whichever matches the armor set you finished. The real decision is drill against pickaxe. A drill digs quicker straight out of the box and reaches fewer tiles from where you stand, and it ignores every mining speed source in the game: potions, the Mining armor bonus, accessories, none of it feeds into a drill. If you have built into mining speed at all, the Solar Flare Pickaxe has already passed it.

Nothing left in the world resists it, which by post-Moon Lord is a formality since you broke everything on the way here. The honest job is bulk work: arena floors, hellevators, clearing a build site. If that is the plan, the Drill Containment Unit sits on the same tier and turns digging into a flying mount, so the handheld version is mostly the cheaper stopgap before you commit that much Luminite.

Reforging is close to pointless unless you plan to hit things with it. Godly and Demonic land in the same place, and neither one makes you dig faster.