I mean, when you get into the physics, physicists are pretty sure that it’s just the 3 space dimensions and 1 dimension of time, and if there are other dimensions they’re almost certainly so small they only become relevant on the quantum scale, otherwise things like gravity wouldn’t work the way that they do (like, instead of gravity decreasing proportional to distance squared, it would be proportional to distance cubed or higher because the gravity would basically “leak” into the other dimensions and affect them to, but gravity does indeed decrease proportional to distance squared so any higher dimensions can’t be significant)