[sricochet]

Thank you JSWolf. You gave me the courage to carry on!

the default function of the KFX Output plugin is to use the calibre Tweaks functions for metadata.

In Preferences >Tweaks > Author sort name algorithm I changed the author_sort_copy_method = 'comma' to author_sort_copy_method = 'copy'

apply changes to tweak, restart calibre then convert to KFX. the metadata will be embedded in the KFX file.

Then the author name shows up as the first name then last name order in Kindle Previewer

This however does not change the author layout on the Kindle. I think Amazon is trying to sort the authors by last name, but in this update version, the kinks haven't been worked out and the author names are displayed as Last Name, First Name. I hope that in future updates this is addressed. Cross my fingers.