It's Elder Scrolls.
In 2001 Elder Scrolls launched on XBOX1, it set the bar for a huge expansive worlds, hundreds of hours of gameplay, and it's disc size 3.1GB remained above average for the 4 years to follow.
If last gen was any indication, Morrowind will hold up throughout this generation as one of the largest most expansive games on the console. And the majority of games, even 4 years later, will be~70-80% of the size.