Possible issue with externally SSD- Xbox Series X

Not really...

Xbox Series X games / upgrades / updates has to be installed onto the Series X internal or expansion card SSD,

You can have Xbox One games on your external hard drive that will get an Series X upgrade but the games will need to be transferred to the Series X and then the Series X upgrade will need to be downloaded onto the Series X SSD,

As an example...

I have Marvel Avengers on my external hard drive that will get the Series X upgrade and I will transfer the game over to the Series X SSD ready to download and update the game to the Series X version when available.

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.

So the external seagate ssd for xbox is usb3.0 with 500mbps read and write speed right? I have two of them and i see alot of people saying "its because the external ssds are too slow to play games on,you can only play series x or enhanced one x games on internal or the seagate expansion ssd card" but alot of external ssds are fast enough? No?

It sounds like you are experiencing issues with your Xbox Series X when installing or updating games to an external SSD expansion card. You mentioned that the console freezes or hard crashes when you try to install or update games, but only when using the SSD expansion card. When you remove the SSD card, the console works fine. However, when you try to install DLC on the internal hard drive, the console still freezes and shuts off after a few minutes.

This issue could be related to a compatibility problem between the Xbox Series X and the SSD expansion card. It is possible that the card is not fully compatible with the console or that there is an issue with the card itself. You may want to try using a different brand or model of SSD expansion card to see if the issue persists.

Another possibility is that the SSD expansion card may be defective or damaged. If this is the case, you may need to contact the manufacturer or retailer to arrange for a replacement or repair.

In any case, it may be helpful to check for any firmware updates or other software updates for the Xbox Series X or the SSD expansion card to ensure that you are using the most up-to-date and compatible versions. You may also want to try contacting Xbox support for further assistance in resolving the issue.

This has been covered and been mentioned as it has been a big concern. Right now, yes you can use your external SSD to play Xbox One and Xbox 360 games but you will not be able to play stored SX games on the external SSD. To be able to able to play SX
games they need to installed on the Series X's SSD not the external one.