A chair doesn't really exist, it's just a collection of atoms arranged in a way that can sit on it and along with the gazillions of other arrangements of atoms that can do the same thing we call it a "chair" because it's a very useful way to call things. There is really not much interesting in the gazillions of microscopic variations of placements of atoma that give shape to the same large scale behavior.
You don't care about the individual momenta of the atoms. What you really care about is that you don't freeze or burn your bottom as you sit on the chair.
So while those properties do depend on the observer (because they are meaningful to the observer) that doesn't mean they are arbitrary and any observer can just choose how to see things.
That's why emergence is an interesting phenomenon. Emergent properties are still objective, because we can all agree on them regardless of our mood or culture or agenda
It's a "real pattern", as real as the underlying things it's "layered" on