You can re-import the contents by going to the Site Library.
When you see the “Existing Site Import Detected” warning, just press skip.
Select Read template and re-import all the contents.
But its important to know that the Site Library won’t reimport if the original pages are still intact even though its heavily edited.
For the reimport to work, the original pages must be permanently deleted on trash.
Important Note: This will overwrite any changes you’ve made on the customizer settings w/ the default settings of Read template.