Orbuculum

These crystal spheres can be crafted with four nether quartz and amethyst shards surrounding a single diamond in a crafting table. Once obtained, one can hold the orbuculum in their off-hand to redirect any newly collected experience into it. One can contain up to 30 levels (1395 XP) which will stay stored until the player decides to "cash in" the experience by breaking the item through the use of a grindstone. They cannot be combined with an anvil to combine storage or other attributes.

Orbuculums can also be put into an enchantment table with lapis lazuli to elicit "essence enchantments." When dropped into the enchantment UI, all three options from 10 to 30 can include any category enchantment from tool-oriented to combat-based, and unlike the normal enchanting process, choosing any one of them will drain that exact amount of XP from the orbuculum. This is because the essence enchantments that this item omits will apply to any and all tools, weapons, and armor in the player's inventory, enchanted or not, so long as it remains in the offhand (i.e. an essence of sharpness V enchantment on an offhanded orbuculum will give all swords/axes in an inventory sharpness V). However, should an enhanced tool break, the orbuculum will also break.

This is tremendously OP but it was an idea I had so I wanted to put it down here in case balancing it was ever possible.