A:AnswerYou can add 1 NVME drive per slot. There is not a maximum storage size for the drive but cost is usually the limiter. Large drives are super expensive. I would recommend a 512 gb or 1TB second drive. Most people run the Operating System on the included drive and then add a second to install their games and any large applications on.
A:AnswerIf you're referring to Bluetooth connectivity, This laptop does include Bluetooth that would work with your Xbox controller. (Assuming you have the latest controller)