The interactions between the magic design and alchemical systems can be emergent, but you're right that the cancelling of the negative effects of the OP items c

The interactions between the magic design and alchemical systems can be emergent, but you're right that the cancelling of the negative effects of the OP items could be called synergistic instead - I think it depends on whether the effects were intended to be cancelled or not, which I don't think they necessarily were given the ones I mentioned were both introduced as jokes and items that are OP with a significant negative effect are usually coded as cursed or xeno-objects, and afforded a high status rather than being granted by random passers-by.