Give me a quote saying it's a matter of complexity then or that they will destroy it "fundamentally", the cactus metaphor in itself has nothing to do with anything akin to fundamental destruction, only the physical structure (no, I am not saying they would only destroy the components, but destroying spacetime itself isn't anything special, much less basis for 12D).
That's bullshit, as simple as that, Gabriel was talking about the amount of water in the planet and it's explicitly stated that at worst it would be akin to planet exploding, that's as far from 12D as you can get. Not like the Dragon King ever did anything even close to what you're implying here, the most it did was create a hole in space (which it didn't actually create, anyway, we have no idea if it was literal or flowery language) which also isn't a 12D feat.
Again, give me a quote saying the MGs were too complex for the world, do you actually have something to base this on? All quotes I am aware of talk about the MGs power simply being too much, you're again just saying bullshit.
That's not even close to begin proof of 12D, for the 3rd time, destroying 11D, no matter how you do it, isn't proof of 12D.
Oh right, because Elephants are 5D and Bikes are 4D, for sure.
The more I read what you're writing the more i feel like you don't understand how we deal with dimensions here in the wiki.
What you're missing is that the "existence" that was layered wasn't their dimensionality nor something conceptual of any kind, it was their power and capacity as MGs, that was explicitly stated, you're focusing on a term and not looking at the context it was used.