I have tested several ePub software.
I remember that
Kotobee Author has a weird merge between "Book View" and "Edit TOC".
Here is a demonstration video:
https://youtu.be/WfN-44WRYUw
Each chapter and sub-chapter are individual XHTML, organized according to the final result and order in the ToC.
It's not silly because 1) it's intuitive 2) It's the desired result in 90% of the books.
Obviously, it lacks granularity, and when you know how to use Sigil's "automatic ToC generator", you get much better results.
(But don't judge it too quickly, I just reinstalled the Kotobee for the occasion, so I certainly didn't use it to the fullest)