Netherite items should have an unusual rarity level.

Reasons:

• Ancient Debris can only be obtained in two ways: either mining for a very long time in the Nether while constantly being under the threat of lava pouring on you, or taking even greater risks by looting bastions. Both methods are roughly as difficult as obtaining other items of unusual rarity (if not more difficult).

• When crafting netherite equipment, a netherite upgrade smithing template is used, which already has unusual rarity. Following the rule that if a craft's ingredients have a higher rarity, the resulting item should also have that rarity (as seen with the mace, for example).

• Technically, making this change is not difficult at all, since it would simply require changing the rarity.

In my opinion, these reasons are sufficient to increase the rarity of at least the armor, tools, and weapons, but ideally all netherite-related items.