I think this kind of misses the bigger reason that there isn't a lot of formal discussion on psychedelics; people are worried/nervous to talk about it too openly because psychedelics are "hard" drugs. Even for research purposes, they're tightly controlled which ends up suppressing a lot of practical research and you _have_ to rely on hearsay and anecdata to make a decision.
Edit: Also, as another commenter noted, because very few places allow you to get psychedelics legally, dosage and purity is always questionable; naturally you're going to have a bad time with something that is cut with really nasty drugs if you aren't aware of it and prepared for it, but this is pretty true of most things in life, even those not related to drugs.
Search engines, well, Google at least, are pretty complicit in this too, as it seems that sites discouraging drug use are brought to the top when searching for relatively reasonable things like "safe dosage $drug" or "$drug interaction with $other_drug". Even between different countries, the same search query on google will give quite different results.
I don't think among the people I've talked to that enjoy psychedelics have ever introduced a newbie to any drug without a safety warning and a fair amount of preparation, and in Amsterdam where mushrooms are legal, the shops are quite careful to ensure they are giving you the rundown on what to prepare for, dosages, finding a comfortable and reliable setting, safety, etc.
> but the "how" is largely ambiguous.
Honest question, have you taken any drugs that weren't prescription or alcohol/caffeine/nicotine? Because it's very easy to pinpoint how drugs (especially psychedelics) are life changing, at least for me.
Ecstasy - For a few brief hours, I not only felt good, but thought good thoughts about myself. It was a complete reset after many years of extremely low and dark times in my life, and after that I had a baseline of "hey, I actually _can_ feel good and think good things about myself; I am capable of it." And it was basically all I needed, a single time to break me out of years of depression
Psychedelics - It is an immense spark of creativity and just fascinating to see what your mind can invent and how everything has additional "perspectives", like the color of music, visualizing a world or scene in your imagination that you probably never thought of before, and the good sensations you have amplified by 1000x. Your mind makes connections and associations which sure, with time you could maybe reach sober, but it happens rapidly, effortlessly, and repeatedly on psychedelics, and the experience stays with you. If you've never had a moment of clarity, be it academic, problem solving, etc, then I'm not sure that psychedelics are the biggest concern for you :). These experiences _can_ happen sober, but at least for me, only with guided meditation over many sessions could I reach such an experience.
I'm not sure it's possible to be more specific than this with simple descriptive words, and I think the art and other drug-inspired pieces more than speak for themselves as to how it can be life changing.