Xbox Hard Crashing/Shutting Off While Playing BF6

As I said elsewhere: some initial XSX console batches had a hardware defect that shutdown the console in a variety of games. This is not exclusive to EA or BF. I had one such—I speak from first-hand experience. 

 

As you stated yourself: "(...) an issue with a large number but not all Xbox series X (...)".

 

There's no point waiting for EA/DICE to fix anything about this: as it has nothing to do with them.