I think it's easy to see that psychedelics, while valuable, aren't exactly a direct key to world peace. Why? Because we won't have peace in the world until we have peace in people. And psychedelics, whatever they do, and I think they do something very useful, do not make people peaceful. Even if a person has many psychedelic experiences over a long period of time, they will most likely still be afflicted to some degree by greed, envy, anger, resentment, fear, etc.
When we say we want peace in the world, we really mean we want peace in the human world. And the human world is made of humans. But each person wants peace to be achieved by all other humans making themselves peaceful -- very few people have any practice to make themselves more peaceful.
If you want to make yourself more peaceful, this is the way I recommend: https://library.dhammasukha.org/uploads/1/2/8/6/12865490/the...