There's quite a few non-drug things that can induce an altered state of consciousness like Bungee jumping, hunting, practically any extremely intense activity. Any situation where you truly believe you have a legitimate feeling of facing death essentially activates the ASC. Which is to say consciousness becomes secondary to your body's actions and you experience that separation. You feel your mind and body are two completely different entities and in that ASC your mind is the observer of your body the actor. Essentially everything that is happening in the physical world is being controlled by your subconscience and all the brain power used for normally interacting and decision making is separated and observant.

I have no doubt it's possible to activate this through breath work and various means like religious experiences etc, I've done so myself. A strong psylocbin induced separation is far more intense by an almost incomprehensible order of magnitude.

For an example, let's say you induce a, for lack of a better term, trip from breath work. At no point is it going to get so intense that every aspect of your body and conscience forgets that you are doing the breathwork and you are unable to stop even when prompted by people such as EMT's and police. Physically ending the breathwork will bring the separation back. With Pyscolbin that's not true and the intensity only builds and you could be in this state of unrecoverable separation for 8+ hours. In the reverse, the deep feelings and insight from Psylocbin come in that decline after the peak where everything starts to become real again and your recognition of the world returns and you remember you ate mushrooms.

After that though it's quite reasonable to get that same feeling from any altered state of consciousness.

Just to be clear, I'm comparing it to the linked research and any notions of naturally induced states.

To me, it's similar to that early part of the trip where you get tired and feel like you want to take a nap, only to find that impossible upon closing your eyes and seeing the images dance around. Eventually that part of the trip ends as the energy builds.