'Proficiency' (or 'Knowledge) Enchantment

The 'Proficiency' enchantment would be used as an xp booster.

It would have a max level of 2 and would either be enchanted on a helmet (as proficiency is knowledge) OR on a sword/bow.

Using it would provide 1 extra xp (I) or 2 xp (II) for all mobs killed by the player, except for the Ender Dragon and the Wither.

It would only be obtainable through the enchantment table and would approximately have a 1.09% chance (same chance as getting a soul speed book from piglins) of being obtained. This would give it rarity.

This would help with leveling up but be rare enough to not be abused like you can with other enchantments from trading with villagers or excessively bartering with piglins.