Titanium Sword

This is a bridge weapon and only a bridge. Nothing upgrades out of it, so every bar spent here is a bar not spent on the armor set or the drill, and the Hallowed swords are only a couple of bosses away. If Night's Edge is already in your hand and swinging, skipping straight to Excalibur costs you nothing.

It autoswings and the arc is wide, so it handles the mid Hardmode ground crowd well: mimics, wraiths, the things that wander out of a corrupted chasm. Against anything that hovers out of reach it does nothing at all, and that describes most of what you will be fighting in the same stretch. Keep a ranged or summon option on the bar for the airborne half of the game.