I'm a bit late, and I'm not sure if its too late for this or if I should save this for another thread (which i am completely fine with making my own since its quite a different view), but I have 3 takes regarding this.
For my 1st take, I completely disagree with the "shatterverse" not being a multiverse, its very
clearly stated to be a multiverse, which by definition constitutes of multiple universes. Individual shatterspaces are also referred to as
universes with cosmic bodies to show, and they are even treated as
parallel in size dimensions from each other.
There's even proof of them all having a unique time flow from one another. Overall, its very clear the intention is for each shatterspace to be its own universe. Shadow even calls each shatterspace "
a distorted version of our reality". The prime world itself being its own "shatterspace" from a restored ghost hill being parallel along with shadows statement should easily put a nail in the argument of shatterspaces not being their own entire universe, but heres where my 2nd take comes in.
For my 2nd take, we currently scale the current universe (or the prime world), to 6x bigger than a standard observable universe size because the paradox prism "shattered" it into all these other universes. My first issue with this lies in circular reasoning, if the prime world is considered a universe in the series, and all the shatterspaces are equally considered a universe (with all of them being
parallel, and the
prime world being treated as an "equal" shatterspace to the vest in the ending), why would it be 6x bigger? The prism is already capable of creating multiple
new dimensions of time for each individual shatterspace, and shadow directly says it
creates a distorted version of our reality, with ghost hill being
heavily suggested to be the remnant of the previous one
just without all the shards and is still parallel to all the others in size (
which the ending again points to), so why couldn't the prism have simply created new and more space along with new dimensions of time too? The evidence more points to the prime world being parallel to all the others rather then 6x bigger.
For my 3rd take, regarding the void, I fail to see why it should be considered a 6th universe. as I already mentioned, it is not out of the question that prism is just simply capable of creating more space and new dimensions of time, so it could also create the void too, but the void doesn't have anything of note suggesting its size. While it was previously treated as infinite, the proof regarding this was heavily put into question and refuted
on my own CRT here. The last argument for the void being anything of note in terms of size is that it "contains" all of the universes which would make it a low multiversal structure, but this also just isn't true. It holds what is
directly stated to be the GATEWAYS to said universes. The void is more akin to
flipside from super paper mario that has
dimensional doors that lead to several other dimensions, but flipside itself wouldn't be that of a multiversal structure and doesn't physically hold all of said dimensions, just their gateways, so I really don't think the void is even relevant at all cosmologically for size.
Overall, I think the Prime world should be considered
Low 2-C, and any universe wide feats should use the standard size of a
single universe. The shatterspaces are portrayed as parallel distorted duplicates of the main universe rather then the main universe divided by 5. The shatterverse is still a multiverse that consists of 5 universes, but this shouldn't effect the size of the prime world for the reasons i went over above.