I'll sling some webs with you spidey. As there are many potential dimensions(axis of travel separated by 90 degrees) this may not be the same 4th dimension you described. Regardless, gravity distorts space time along one of these vectors, the issue most have is it is represented as a 2d plane with a 3rd dimensional distortion, but we live in 3space so where is that distortion? Inwards, and by that the opposite, outwards, this is our axis of travel for the 4th dimension, it may be 4toroidal or 4spherical, but if you draw a line from a center point to a circumference and then a tangent line on the point of intersection, you get how many degrees? 90! We have our 4th dimension. This dimension has limits within the context of our world though, the inner boundry is denoted by the planck scale as anything here would have a frequency well beyond the Schwarzild radius and thus create an impassible event horizon. If we tie this last point in with the "roundness" of this dimension, we have all points in 3space wrapped around a singular barrier, plenty of theories already utilize this(looking at you string theory, see: Calibi-Yau manifolds). The deduction from these points is that when you get down to the planck scale there is only 1 point, it is a locus for all of 3 space, and any object that exists at this scale would be highly energetic(infinite) and there would be only one. Our modern science even recognizes standard model particles as point like, that is having no dimension, so they must by necessity exist at this scale if this is true. Here is the rub, how do you manifest out of an event horizon? You have a naked singularity (https://en.wikipedia.org/wiki/Naked_singularity). In fact electron's fit mathematically very well with the equations necessary to create a naked singularity, see attached document.
Anyone has access to this space, not from empirical observation(impossible to scan this scale with our technology due to energies involved) but within, remember our axis of travel is inwards. This is what mystics have been telling us for millennia, look inwards!