Yes I read it and it is a different Multiverse, re/created by the Maker instead of the main one re/created by the 616 FF. It should exist within the Marvel Megaverse.The What If comic about the 2015 Secret Wars released, and the writer basically confirmed it takes place in a separate multiverse entirely
So with that being said, it could stand to reason the Battleworld is in fact a multiversal singularity