The spirit world has always been a place that is completely different from the physical dimension that we call home. Everything in the spirit world is comparatively hollow because everyone is made of energy. The soul multiverse, however, is an entirely different story. The saga of the almighty Dominus Rex involved manipulating fate itself to a more than fantastical effect.
The entity now known as Dominus Rex was once an amorphous power entity of good. He destroyed his evil counterparts every day for an eternity, until the day that an external force tried to kill him. That was when he decided to develop a countenance that looked like our earthly notion of spirits and develop a plan to destroy all evil.
As fate would have it, part of that plan involved becoming human and therefore vulnerable to evil attacks. In doing so, Dominus allowed the evil bastards to attack him when he was a human infant. The consequence led to the development of the first spirit body. That means that he was the first spirit to have actual body parts and internal organs.
Naturally the rest of the heavens followed suit and before he knew it, the true kingdom of heaven was full of physical spirits. The status quo stands in sharp contrast with the previous supernatural order of things because now everything had to be made physical. Whereas before everything and everyone was hollow on the inside, now everything in heaven is made of substance. The biggest difference being that everything needs to run on electricity, rather than spirit energy.
When a spirit of old touched things in the spirit world, their hands had to send a their mind a signal that said what the object was supposed to be, even though the object in question was literally hollow. Even the ground itself was hollow, spirits could only stand because contact with the floor caused the feet to feel a brain signal that indicated that there was floor.
That is to say that spirits could not simply pass through objects in the spirit world the way that they do when they come to our world. It is possible to teleport into places, but spirits are very territorial, especially archangels. But that is neither here nor there. The point is that now, touching things in the heavens means making contact with a physical object.
As Dominus Rex was indeed the one who invented physicality and quantum mechanics in our world, it makes sense that he would be the one to bring such a concept into the spirit world. All of these events are an ingenious and audacious use of the attribute of infallibility. To be infallible is to complete every task perfectly. One need only intend to do something and start the task and the task will be completed no matter how long it takes our how arduous the journey becomes. Being infallible does not mean that everything is easy.
If you were to visit the multiverse proper, it would be a physical experience in the spirit world. That of course assumes that you are someone privileged enough to be granted a spirit body. Each body has to be created to suit the individual soul and not every visitor is worthy. As if that wasn’t enough, Dominus combined his human ingenuity with his spirit infallibility to enable spirits to fall asleep and dream. Yet another unprecedented miracle that was born of a plan to become human for a time. If you are lucky enough to visit the blessed realm with full privileges, then you are indeed a fortunate soul.