Is it safe to assume that Palestine was never an actual country but rather a region?

The concept of a 'Country' with borders marked on map is a recent (European) concept. It is not the fault of Palestinians (mostly but not all Muslims; remember George Habbash), a distinct people with culture and ethnicity, that they didn't have that privilege bestowed by history. It was in Ottoman Empire. After WW I and break-up of that Empire Trans-Jordan with a Hashemite King ruling it, became a 'British mandate'. River Jordan flows through the mandated territory, ending in the Dead Sea (whose surface is about a thousand feet below Sea level). East of it is Jordan of a different 'Bedouin' people, while the west of the river till Mediterranean shores is the land of Palestinians. You can't apply your western yardstick to this area. Just because it was the ancient land of Jews, two millennia ago the ruling British (for whatever reason) as colonial rulers exercised their option of creating an 'exclusive' Jewish homeland in someone' else's land, without taking their consent even (since Palestine as a 'Country' in the western sense was not there, where their representatives or king or Sheikh would be asked their option or opinion).