Which direction does current flow?

If I make a bi-metal junction then one side will be electron rich while the other side will be hole rich.

Well not true actually as both metals will have electrons as their majority conductors.
My point was that holes were not invented because the early workers got the current flow wrong, they were invented because of doped semiconductors where the majority of charge carriers are positive, and it is a more valid a concept to talk of hole flow than electron flow.

It's easy to treat electrons as particles when dealing with electricity -up to some point- but that's not to say that electrons are particles or that any model we have is the full correct description.

That is very true.

Whatever is happening, it is simply beyond logical explanation.

But that is not.
The explanation has to be logical, it might be counter intuitive but it has to be logically consistent with itself and the rest of physics. What Godel was saying was that there was a class of problems that you could prove, couldn't be proven. But this did not apply to all problems but mainly those that were self referencing.

About two years ago I was part of a team interviewing some one for the post of head of the power supply group. On his CV he said he was the person who invented gold plated mains connectors for hi-fi. I was looking forward to the interview. After an hour myself and a colleague were called in to do the technical questions. He floundered on the first two power supply ones and asked to be excused for a bathroom break. We waited for his return only to find he had run away so we never got to ask any questions about that.