One universe has "observer" (a bunch of variables, really) in one state, another has it in different state. Those variables encode some information about themselves, so indeed in different universes the different "versions" of the observer are different, and each perceive it as universe randomly deciding to chose their version of existence. So what?

We're parts of the physical reality so trying to describing physics from the point of view of an out-of-universe observer, while psychologically attractive, is ultimately futile: in QM, such approach breaks very quickly.

I'm not sure whether eg the Born rule is enough by itself to explain how (non-linear) chaos arises from linear QM.