QM cannot simultaneously be local , deterministic , and real . Unitary QM rules microsystems between measurements. Measurements are deterministic, nonlocal events. Only wavefunctions, not actual particles, behave nonlocally, fortunately. Since relativity can't be formulated nonlocally, let's give up on field theory for now.
Measurements are local, nondeterministic events.
Same as Everett, except for asking questions with a beginning and ending boundary condition, rather than just a beginning and open time evolution from there. No one anywhere is arguing about the math, only about what it means . Anyway, quantum computing no more proves many-worlds than the phases of Venus prove heliocentrism. But in both cases the new facts eventually do direct the strokes of Ockham's razor. The Shor algorithm is a lot more specific than most people realize.