The key distinction here is between dying and all of the unpleasant stuff that normally comes with it. I've experienced loss of body awareness with LSD, psilocy

The key distinction here is between dying and all of the unpleasant stuff that normally comes with it. I've experienced loss of body awareness with LSD, psilocybin and DMT. But what didn't come with it was pain, cardiopulmonary stress, cramping, and so on. So it was easy to relax, and let go of body and consciousness. With just naked virtual awareness left. So anyway, I can imagine that a pleasant death from opioid or barbiturate overdose might be comparable. Or maybe breathing helium, where there's no overt respiratory feedback. Or maybe hypothermia, although in my experience that involved too much twitching around.