No you're thinking of MWI all wrong. Your conception of the universe you exist in as being non-quantum is fundamentally flawed. The universe with the superposition of all the possible observers exists more purely in hilbert space. Sean Carroll has even started to put together a model for how spacetime could emerge from that hilbert space.

So the universes all exist in the same place, since they are the same universe. Your idea of what an observation is, is just an eigenvalue of that corresponding operator.