Thanks for the video. He mentioned that the pilot wave is made up of "some stuff", but never got back to that being one of the unknowns of pilot wave theory. Seems like that questioned will need to be answered before it is taken more seriously.

> He mentioned that the pilot wave is made up of "some stuff"

Could the stuff be dark matter or dark energy?

Pilot waves aren't made of anything, they are a description of configuration space. Think of it like this: to describe particle motion, take the ordinary/classical equations of motion, and now add another term to account for quantum behaviour. The force exerted by this term at time t is a function of the position of every other particle in the universe at time t, no matter the distance.

That's pilot wave theory, where this term is sometimes called the "quantum potential" and is governed by Schroedinger's equation. As you can see, this extra term goes to zero when quantum effects become negligible and we recover classical mechanics straight away. The difficulty is the obvious nonlocality and what that means for special relativity.

Could this connection to the rest of the universe be considered conceptually similar to a form of entanglement?

Sort of. There is no real entanglement in this formalism, not in the way it's typically portrayed. I suppose you could say entanglement is there all the time. Macroscopic observation of entanglement via non-local correlations is really just a context in which we make the non-local connection observable.