The issue is Calibre uses only ONE DB per Library (listing)
The DB resides in the root of the Library (the folder name IS the Library name)
The basic internal structure is Author Folders alongside their DB. Not format, not size or anything else, Authors.
As you are aware, A VL is just a (restricted) View of the overall, so you could have a VL for coffee table sized (>MB) books [ {size}>2000000 } (note this value is not just a single book, but the contents of that Title record)
That leaves a distinct,
separate Library as your choice
But
You could add 'EMPTY BOOKS' (a book without Formats), tagged: "In XYZ Library" (which you switch to). The drawback is this is a High effort maintenance model (Every BIG book added/changed needs the mirrored empty book metadata)
So, what are you really trying to
cure by doing this?