Q: Is destroying multiple infinite multiverses a better feat than destroying a single one?
A: In spite of what our intuitions may tell us, destroying or fully affecting multiple infinite-sized multiverses is in fact not better than doing the same to a single infinite multiverse, and thus, not above the "baseline" for 2-A.
The reason is that the total amount of universes contained in a collection of multiple infinitely-sized multiverses (even one consisting of infinitely many of them) is in fact equal to the amount of universes contained in a single one of the multiverses that form this ensemble: It is countably infinite, as the union of countably-many countable sets is itself countable, and thus does not differ in size from its components. The only general difference between multiple infinitely-sized multiverses and a single one is representation. What is considered to be multiple multiverses in one fiction could be considered a single multiverse in another, and vice versa, without the objective properties of those collections of universes changing. The only difference is where an author decided to draw the line between what belongs to the same multiverse and not. Thus, only an uncountably infinite number of universes actually makes any difference in terms of Attack Potency, at this scale.