I believe that a lot of the "awakenings" and spiritual nonsense associated with psychedelics stems from how they interact with the brain and the fact that people tend to underestimate how much their brain doesn't for them. Hell, some people don't seem to realize that they basically are their brains (i.e. The brain gives rise to the mind). I remember having a few moments where I felt "spiritual" while high on shrooms, due to that feeling of interconnectedness I felt while tripping. The thing is those spiritual feelings likely stem from how psychedelics impact the areas of the brain involved in the self.
The reason why your "I" self (this refers to self as a subject) starts to fall away when high on psychedelics is because is likely due to them messing around with the areas of your brain involved in things, like multisensory processing. For context, bodily self-consciousness is believed to be the result of multisensory integration. They also impact brain networks, most notably the Default Mode Network (DMN), which I am pretty sure is involved in the "me" self (self as an object). The DMN is involved in many things, including the retrieval of autobiographical memories and self-referential thought. It plays an important role in self-narrative. DMN disintegration is correlated with ego dissolution and psychedelics happen to be correlated with decreases in the functional integrity of the DMN.
Basically, what I am saying is that the spiritual experiences that come about due to psychedelic use are likely not due to things, like us being part of some sort of collective consciousness, but rather stem from how they alter areas of the brain that happen to be involved in different aspects of self-consciousness. They change the boundaries between oneself and their environment, similar to what we might see when looking at something, such as the rubber hand illusion. The main difference is that while the rubber hand illusion involves incorporating aspects of our environment into the self, psychedelics instead break down the walls between our sense of self and the environment.
I don't know what you mean when you say that ego death is the "truth". I mean, psychedelics don't even reveal any "truths", at least not objective ones. The conclusions you come to while tripping are based largely on you. They are based on your knowledge, how you process the world around you, your personal experiences, and so on. There are people who use psychedelics and go on to come to ridiculous conclusions.
Psychedelics are just a class of psychoactive drugs at the end of the day. They are very interesting drugs and come with some very unique effects but they are just drugs. I'm saying this as someone who happens to love tripping on shrooms and who plans on trying some other types of psychedelics out before ctbing.
The suicidal impulse that people get while high on psychedelics, such as shrooms, likely has to do with the fact that psychedelics tend to heighten our emotions so somebody who is already dealing with suicidal ideation might find that psychedelics happen to heighten those feelings. This is just me guessing, btw. I would imagine that the suicidal impulse thing would only really be an issue for those who are already struggling a lot with suicidal ideation. Psychedelics also can do the opposite as well, and help those suffering from suicidal ideation. I would imagine that whether they cause increases or decreases in suicidal ideation and impulses probably has to do with factors, such as the context under which they are being taken (e.g. recreationally, as part of a therapy session) and whether or not the trip is good or bad.
I also feel indifferent to people taking psychedelics while ctbing. I'd imagine that they would probably just be doing it for the same reasons why people take depressants before ctbing, which is to lessen the effects of the SI.
