I’d say it’s more like annealing. Sort, filter, compress, integrate.

Updates your models for the next morning, which is why the answer is there when it wasn’t before.

I assume most people agree with that framing. “Thinking” generally implies a level of consciousness or self-awareness.

“Let me think about this.” “I have to think on it.”

My brain regulates all sorts of processes unconsciously, like breathing, for example. I don’t treat those as “thinking,” so I don’t know why other unconscious brain activity would be either.