Less about the psychedelic experience itself. I also think that the existence of these drugs show that someone's reality is constructed from chemicals and cells doing what they do. Psychedelics are like throwing a wrench in a machine. The chemicals and mechanics are working differently now and the conscious experience changes with it. Depending on the drug introduced the perception changes, or consider some drugs like anesthetics where you can be awake and responsive but not have any personal awareness of whats going on.
On DMT trips I felt abstract thought fall apart along with the idea of my self(Ego death maybe?). I couldn't form ideas, and there was no longer an idea of self. "I" didn't exist. But this happens because a chemical is introduced into a system that is generating a conscious experience and it changes because of it. A typical brain creates these abstract ideas, your self identity, interprets senses in a certain way. That's the illusion created.
Since drugs being introduced into the system can turn off that sense of self, I, your soul(anesthesia, ego death) I don't think dualism is really applicable, the mind seems to be generated by the brain/body and its chemicals.
Hope i explained my self alright, not a topic I get to talk or think about much
Have you ever experienced your sense of time becoming immaterial? I've had one such trip where I genuinely believed that time stopped, and I was present in some eternal plane, though my ego no longer was present. I can definitely see how such an experience could lead someone down a path of panpsychism.