You could use KRDS
https://www.mobileread.com/forums/sh...d.php?t=322172 and bits and pieces from KindleUnpack
https://www.mobileread.com/forums/sh...ad.php?t=61986 to extract highlights and notes from the contents of the azw3* files and the book itself. The highlighted text might have HTML embedded in it.
It would probably be quite a bit of work