Does anyone know how you’re supposed to make the environment behave like a living organism?
I don't know, maybe it be like if you were in a tunnel, the environment could close the tunnel's entrance so you had to find another way out, or maybe if you had like a spaceship or something that flies, if you got too close to the planet's surface, it would try grabbing your spaceship and making it crash or pull your spaceship into the surface so it would get buried or something. If you are asking about animations and models and stuff, I have no clue. Personally, I avoided that diversifier because it seemed super complicated to me.
The easiest way I usually make my environments feel alive is through triggers that change up the appearance. Usually when the player can't see. It's cheap and performant but still makes it so it feels alive and dynamic. You can do small changes or big changes, but try to place them at key moments the player goes through. That way it feels like the player's actions have caused a pretty massive shift in the environment