I was watching this car review. They were looking for an USB port in the back of the Mazda, and one of them said "It's in the central armrest. You have to flip it down"
Now, can I say 'unfold' it like we would in Polish?
No, both describe the same movement. “Flip“ to me suggests something a bit easier to do, and quick, like flip the switch (on a light), flip a phone open, flip a book open etc. In my experience, car armrests are a bit stiff, so you have to put a bit more effort in to doing it. Hence my preference for “pull”.