The above examples at least had the key word "Chapter", Which I believe Calibre factory defaults will trap correctly
Other common: chapter headings: Just digits or Roman Numerals, which are fairly easy to spot and trap with a REGEX expression.
If JUST the numbers are Spelled out (Seventeen), Or the Chapters just have words (A Golden Harvest") things get tricky. Hopefully you will find a unique pattern before and after, you trap on.
(I use trap, to mean a Search pattern match