If we knew how to create world simulation, and how to make it working 4D, then humans would be able to plug themselves in, and experience 4D space. Alternatively there could simulated 4D beings, whose sentience could be transferred to robot body in our real 3D space.
If there were a 4th spatial dimension and you could see in 4 dimensions, yes, you could see the inside of things that are enclosed in 3 dimensions. It wouldn’t be like x-ray vision exactly though. Think about a sphere in 3d. It is enclosed. When you take 2d projections of the sphere by slicing cross-sections of the ball, from a 2d observer on that plane, they would also see an enclosed circular object. But from the 3rd dimensional observer looking down at that cross section they can see everything enclosed in the circle. From the 4th dimension, then it stands to reason they would have a similar view of a 3 dimensional objects innards. But rather than seeing through the object like in an x-ray, they just see the whole thing laid out in every detail at once like we see the insides of the 2d circle.
I think it would depend on how the shapes extend into the 4th dimension.
Where the 2D slice is two circles: if in 3D we have a sphere inside a sphere the inside is occluded, but if we have a ball inside a cylinder the inside is visible from two ends.
Likewise where the 3D objects are a ball inside a ball, they may be two 4D spheres or one might be more like a cylinder.