Spacetime exists for humans as we know it. Our reality and experience is valid. But, to beings with a “higher” vantage point, spacetime is much more flexible.
Time is inconsequential and space is easily crossed. Additionally, there is evidence of multiple realities to exist within the same part of spacetime.

We also, have the concept of curled up spacial dimensions but truly spacial dimensions as we know them are the “curled up” dimensions.
They are less prevalent than we imagine. Spacial dimensions are manifestations of emotional realities.

The embodiment of higher emotional realities looks a lot less like physical reality as we know it.
Higher dimensions exist spacially, in ways we have difficulty comprehending,
but these new spacial dimensions do not exist within the same framework as the ones we know and love.

Instead, they expand not blooming out from the 3rd dimension in some “bigger” way, but in the embodiment of emotion and love.
In this way, the new age ideals of dimensional reality and spacial reality theories are tied.
Multidimensional theories of simultaneous realities are a separate but related concept to which dark matter and dark energy are the keys.