Empowered Weapon

You touch a weapon. Until the spell ends, that weapon becomes a magic weapon, if it wasn’t already, with a +1 bonus to attack rolls and damage rolls, an additional +1d4 damage, and changes damage type depending on the target. If the target has a Vulnerability it changes to that damage type, if the target has no Vulnerability but has Resistances or Immunities it changes to the damage type that would do the most damage, and if multiple damage types meet these criteria then the attacker knows them and can choose the type they attack with.

At Higher Levels. When you cast this spell using a spell slot of 4th level, the bonus increases to +2 and +2d4. When you use a spell slot of 5th level, the bonus increases to +3 and +3d4.

Alternate Classes. This spell was made for the Artificer Weaponsmith subclass and their Battlefield Smith feature, but if it were being used by other classes the following changes would be appropriate to match Magic Wespon and Elemental Weapon, Spell Level 4th, Casting Time 1 Action, and At Higher Levels going to +2/2d4 for 6th and 7th level slots, and +3/3d4 for 8th and higher level slots.