Unmerge cells and copy content

I have a big table with many merged cells copied from an html document, like this:
image
I am trying to reorder the columns and rows, so I need to unmerge these cells.
however, when I select all and unmerge, only the top left cell of each merged section retains content.
is there a better way to copy the content to all child cells? I feel like there should be two separate unmerge cells - restore content and unmerge cells - duplicate content buttons.

https://forum.openoffice.org/en/forum/viewtopic.php?t=62069

did you mean to comment this on another post? I don’t see how it’s related to my question