Answer
To batch replace some texts in bookmarks, please follow these steps:
1.Open the PDF file whose bookmarks you need to batch edit. Expand the bookmark panel on the left side.
2.Click on the first icon at the top of this panel called 'Options'. In the dropdown menu that appears, please select 'Export All Bookmarks'. This will export all bookmarks from the currently opened document to an XML file.
3.Open this exported XML file containing the bookmarks with MS Word and use 'search and replace' in Word to edit in bulk.
4.After making the changes, go back to the PDF file. Delete all the current document bookmarks (you can hold the shift key, click on the last bookmark and then the first one to select all bookmarks in the current document, right-click on these selected bookmarks, and choose 'delete' from the pop-up menu).
5.Then, use the 'import bookmark' feature under the 'Options' in the bookmark panel to import the bookmarks from the newly edited XML file.