I agree with your conclusion that the pineal gland and what it does is some major hippy shit, but then, I'm an old hippy, so I'm good with that. :-)
The pineal gland is said to be the source of DMT in your brain and body. If you want a real trip down a rabbit hole, read up on DMT, dimethyltryptamine.
Here's good place to start that.
https://en.wikipedia.org/wiki/N,N-Dimethyltryptamine