When I moved to series X, I justed logged in using my profile, if your refering to profile data, this is not only kept on your systems hard drive, but on Microsofts Azure servers also, so theres no chance of you losing it. As for games can swap em using any external HDD/SSD. If you have a lot of games on a external, might be worth getting a external nvme SSD, (once downloaded games can be swapped back and forth within a couple of minutes), others work fine and don't need the super expensive series s/x dedicated one.