Is the external hard drive not playing X/S games a new thing? I fell like I've been playing...

It's only on the Series S/X that they can't be played on a regular hard drive. The hard drive is too slow to run the games properly. The One is fully capable of running all games from the internal or any external hard drive. The One wouldn't have been playing optimized games at the full S/X optimization due to hardware limitations.

If you were playing a series game, it must be played from the internal stogars on the Seagate expansion. Other hard drives are exponentially slower, and cannot keep up

It has always been this way

If he has a Series S/X and is trying to play a Series S/X optimized game, it will only run on the internal drive or on an expansion card made for the Series S/X. It won't run on a regular external hard drive or SSD.

Hi,

External hard drives are not fast enough for Xbox Series X|S titles. Unfortunately you can't play these games off slow USB external hard drives. They need either be installed internally or to an optional Xbox Series X|S Expansion card.

If they're Series S/X games or enhanced games, they can only run on the internal hard drive or the Seagate expansion card made for the Series S/X. A regular external drive can be used to store the games if you're not playing them and store/play older games.