I think there is a lot of things that shrooms do, and a lot of things they don't do (like open portals to alternate realities).
They're good at "shaking the snow globe" so to speak. Breaking up repetitive behaviors and introducing chaos. I also do think that they allow us to see the world a different way. How humans perceive the world is now how the world actually is, and shrooms can provide us the ability to experience and understand that we do not live in an objective reality.