I am trying to copy the bookmark structure from a previous bookmarked PDF document I published, and need to paste it into the newer published PDF document and maintain the links of the previous bookmarks.
Why not just replace the pages in a copy of the original PDF?You have to be sure that the all the bookmarks are still pointing to the correct page.
PDF Bookmarks are not "page content". It is not possible to "copy-paste" these..Be well...
Since you mention that your PDF document is structured - meaning that that it has tags, you can also build your bookmarks in one step using the various pieces of the structure.You can pick and choose what structure tags to include or not include.