Bell's inequality *was* about hidden variables. Here's the first paragraph on the subject from Wikipedia:

"Bell's theorem is a term encompassing a number of closely related results in physics, all of which determine that quantum mechanics is incompatible with local hidden-variable theories given some basic assumptions about the nature of measurement. 'Local' here refers to the principle of locality, the idea that a particle can only be influenced by its immediate surroundings, and that interactions mediated by physical fields can only occur at speeds no greater than the speed of light. 'Hidden variables' are hypothetical properties possessed by quantum particles, properties that are undetectable but still affect the outcome of experiments. In the words of physicist John Stewart Bell, for whom this family of results is named, 'If [a hidden-variable theory] is local it will not agree with quantum mechanics, and if it agrees with quantum mechanics it will not be local.'[1]"

So you're over-generalizing here. Yes, it's true that non-local hidden variables can't be ruled out. But you're then assume theres these incredibly complicated non-local physics guiding these interactions that we can't see, that appear stochastic to us, but are deterministic in some other frame. This is why I originally said hidden variable models are trying very hard!

Also, that's just not what many-worlds says. Your characterization of world splitting happening at every Planck-scale interaction is just wrong. That shows a deep misunderstanding not just of Everettian thinking, but of quantum decoherence itself. A human being and your environment is an almost entirely decohered quantum stream. All the many-worlds interpretation says is the world evolves according the Schrödinger equation. That's it.

If you take the Schrödinger equation seriously, the other worlds show up for free. Every other interpretation, including Bohemian mechanics, is trying to argue for the deletion of those other worlds.