[millstone]

> the Everett interpretation does have one issue: it's not clear why probabilities should work the way they do.

This is referencing the nature of the measure and the difficulty of deriving the Born rule. Why should the outcome of measurements be proportional to the square of the wave function? That's indeed a problem in MW.

But even if that's solved in some way, there's an even more foundational issue of how non-determinism can arise at all in a deterministic theory. The MW reply is that there is no non-determinism, but then has trouble explaining observed reality - which is not a good position for a theory to be in.