move an existing xbox series x game to a new drive

Fair enough, a slow internet connection is as good excuse as any.

Be aware however that while that drive will work on Series X, you won't be able to play Series X games directly from it. Series X games will require faster access and read speeds. My understanding is that the Series X games can be 'backed up' on an external
drive and then need to copied/moved over to either the internal SSD or the External SSD's that will be available for the machine.

The Series X will read and play Xbox One games from an external drive though.

Then yeah, you can plug it into the new console and use it like that or transfer from the hard drive. Any games that are optimized for the Series S/X will not run from that drive, but you can store them on it. So you may have some games that will have to be moved to the internal drive on the Series S.

Hi,

If your game is now a Series X optimised title, it can no longer be played off an external hard drive. It must be moved to either the internal storage or an optional expansion card.

External USB hard drives are too slow to play Series X optimised games. None Series X games will still run from your external drive. The internal storage in the Series X is a fast NVME SSD. These drives are several times faster than mechanical hard drives.

Are you talking about series x or patched games ?

If so then no you MUST move them back onto internal drive for series x to work

No, just plug in the external hard drive, and your games that are stored on there will work straight away. There is no need to move them to the new console, only the Xbox Series X games have to be stored on the console or the external SSD storage that
is available for it too.