Delate untouched chunks timer for smaller worlds

Recently I got a big concern about my personal world, the cloud space for my xbox series x was full, and my world (that takes all the space about 830 megabytes ) wasn’t saving in the cloud, it was saving in the local storage, and when I was updating minecraft to the chase the skies update, about 3 months of work was gone, and the I was back in the last cloud save, with these idea I propose a timer(that timer has to be very long if someone is planning to do something in that chunk) or an option to delate untouched chunks to make the world smaller and don’t have any cloud problems.