Lost game ownership.

That would be possible, but then that wouldn't make sense because the one person I'm game sharing with is having the same problem as me with the same game. So if one of us lost ownership, the one who bought it, they would both lose ownership. I will talk
to him about it and have him check his billing as well. Thanks for your time.

Then you need to contact in game support as you have lost ownership on In game items, and they will be the ones that can help you on that

https://help.minecraft.net/hc/en-us/requests/new

Hi there xl Irritum lx,

Thanks for the reply. I'm sorry to hear about the issue with backwards compatible DLC for the Xbox One. I recommend try the following troubleshooting article:

Troubleshoot playing Xbox 360 games on your Xbox One.

• If you have the digital license for the Xbox 360 game and it’s available to be played on the Xbox One, the game will appear in the
  Ready to Install section of My games & apps.
  
• You can check whether you have the digital license for an Xbox 360 game by visiting your
  
  Purchase History. To see whether an Xbox 360 game is available to play on the Xbox One, see
  
  Play Xbox 360 games on Xbox One.
  

If the problem persists, try reaching out to the game developer for more assistance on availability for backwards compatible items/licenses.

Hope this helps.

I purchased it like 8 - 10 years ago and almost no DLC from that far back appear on my purchase history. Also, the removal of my account did nothing.

Hello
xl Irritum lx!

Thanks for reaching out to Xbox forums support. I understand you're having issues with missing DLC on your backwards compat game.

First off, I would recommend checking your
Microsoft Purchase / Order history to make sure the DLC purchases appear on your account.

Next, I would suggest making sure you're signed into the correct Microsoft account that owns the DLC.

If those 2 steps don't resolve the issue, try
uninstalling / reinstalling your Xbox profile from the console.

Let us know if that helps!

Good luck and happy gaming!

Felix

Xbox forums support