here Note: all observations in MWI ends up with observer de-cohering.

It's rather easy to misunderstand Bell's theorem and overstate it's applicability. It's a bit like how relativity doesn't prevent a dot of laser projector from moving faster than light on far away enough screen.

Bell's theorem rules out local hidden variables that move around together with particles. It doesn't rule out locality in general, and doesn't rule out lack of randomness. (MWI doesn't have any objective randomness)

Something tangential. In CS, the "non-deterministic", as in "NP-complete" and "non-deterministic Turing machine", is the machine that would fork or would magically pick the transition that leads to solution, rather than machine that would choose some truly random transition from the list.