I may be mistaken, but wouldn't the magic item be the material component in the same way a spellcasting focus counts as a material component.

I think one of the main problems I see other people have it is the pointlessness of it. The target does not lose a spell slot, but you do. You delay the casting by one round, so unless your team can do enough damage to the enemy caster in that round or the caster is about to kill a team mate and you need to give the others time to force feed them a potion or have the cleric heal them, it seems like a waste of a spell slot or a known/prepared spell.

I personally disagree with the "a 3rd level spell can cancel out a 9th level spell" discourse because that was a thing that you could do with the old counterspell anyways, but I do agree with the problem of it not losing that spell slot, because the archmage may still power word kill a party member a round later. If it is going to be a saving throw, and thus introduce a chance of failure, either allow upscaling to increase the DC that the enemy spellcaster has to clear, or a least have it waste the spell slot so it can feel like you are doing more than just staling them.

It can still be useful, don't get me wrong. If you are fighting one powerful lich for example, you completely waste the lich's turn, essentially giving your party members an extra free turn which can turn the tables in a fight, but because their is a chance for failure now, maybe have it that a spell slot is wasted on the enemey side, or if you fail, you don't expend a spell slot