A lot to unpack here. He espoused a worldview where human beings are "star stuff", a way for the Universe to be self-aware.

And this worldview does not exclude spiritual thinking, it just channels it in a specific direction.

Yes, he said our brains are made from the same matter as everything else, but it does not follow that he espoused any sort of strict materialism.

The truth is more subtle and nuanced than that.

If you are interested in getting inside his head, I recommend reading the Mr. X article.

https://marijuana-uses.com/mr-x/