Version: Beta 1.2.10.5 (for Minecraft 1.18.2)

Since the Crystalline Sword automatically enchants itself with Sharpness 4 when placed in the inventory, you can repeatedly grindstone it to remove the enchant for free xp. It'll immediately re-enchant itself without even needing to close the gui.

If you want to have it come pre-enchanted, I suggest you do so with the crafting recipe itself (like what Twilight Forest does with ironwood and steeleaf tools).