I'm trying to design a magic item that can eat other magic items to gain their abilities. However, I keep running into a problem. Eventually, the magic item becomes semi-omnipotent as the abilities stack, leaving no weaknesses.
Context: Magic items in the world are common and have a multitude of different abilities ranging from combat focused ones like damage absorption, to support ones like speed increase and utility ones like search (checks the area for hostiles and items). Some magic items' abilities are stronger than others, the stronger the ability, the rarer they are.
I want the item to gain a plethora of abilities while not allowing it to get too powerful. So what would be a plausible solution?
Do these items have charges? - The items have a set number of uses depending on their grade from 1-10 (10 being the highest). However, extremely rare items have an unlimited uses, such as the magic eating item itself.
Do you have to activate them? - Some do, others are passive and slowly run out of durability until unequipped, and those can be repaired.
Can they get damaged when you use them too often? - See above.
Can they overheat? - No.
Could they explode if used wrong? - No. Explosions only happen if its their intended function.
What would two conflicting enchantments do? - They can't be on the same item.
Are very powerful items also unstable or harder to use? - Just extremely rare.
Do you have a magic eating monster or a crazy lich collector actively looking for these items? - No.