Hello Azaghal 1751, I hope everything is going well!
Thank you for reaching Microsoft Xbox Forum support!
You can manage your data for individual games through My games & apps on your Home screen. Here's how:
On Home, select My games & apps.
Highlight the game, press the Menu button on your controller, then select Manage game & add-ons.
Select the Saved data box, then choose the item you want to delete.
I wish you a lovely day, and I hope this answers your query!
Stay safe, and happy gaming!