Backstory for settings and campaigns rarely have any meaning for PCs beyond the thin explanation of who they gotta kill and loot this time around.

The Backstory is for the GM. I am regularly praised for my DM-style because it is heavily sandbox and my players generally love that there is ALWAYS something new whichever direction they take. I know everything about my universe, and so I am able to convincingly improvise on the spot endlessly. If I didn't know the backstory, could I keep my players entertained in this way? Of course not.

Your GM friend has a different style. Keep to yours.