"And PlayStation has had quick resume since the PS4."
That's not Quick Resume. Xbox One had that feature since day one, then PS4 few years later after release. With Quick Rusume on Xbox Series you can play the game where you left off, from cold restart, after playing other games.
You do realise Microsoft Flight Simulator 2020 Base game is 42.4 GB on Xbox Series? You can install the Offline mode for 59.7GB, making it 102.1GB. It's optional.