Xbox series x codes

If your game code only says it is for Series X|S then it will not work on an Xbox One X. The One X was the revised Xbox One hardware released in 2017, it's not the same as a Series X.

I am thinking of buying hogwarts legacy as a digital game but it is sold out for Xbox one so should I buy the Series X game and put the code in the Xbox one Store?

No. The series X/S version of the game will only work on the Series X or S.

The only way that would work is if it's a code for the digital deluxe version of the game (which comes with both the series x/s and xbox one versions of the game)

I was under the understanding that when you download an Xbox series x game it has different code, so it wouldn't be possible on xbox one x. Which would also be the same for the hard drive. The xbox series x game is apparently different than the same game
for the series x.

That's why its just called Xbox... and the other series or models will be called series x and possibly other series code values yet to be determined officially

I am having the same issue and same error code (80151912) when I'm running the Xbox 360 emulator on my Xbox series X.

I can sign into Xbox live on my Xbox series x but not on the emulator running the Xbox 360.