Welcome Danielle,
I don't know of a way to do that, but perhaps @try67 can develop) a script. I present a possible scenario, using a powerpoint document that contains notes located within the "Notes" section, as shown below.
So try this:
Make a copy of your PPTX file.
Then change the file extension to ZIP.
Double click the zip file to open it. This converts your pwoerpoint to a bunch of XML files.
Do a search for "Notes Placeholder" within the contents of that folder.
You'll see that there are a bunch of instances of that phrase.
If you view the contents of one of those XML files with a text editor (like BBEdit), you can see the contents of the note.
I would imagine that there is a way to extract the contents of those notes (adjusting for required elements of a note in Acrobat, such as date, author, page position, etc.) and make a new XML file out of them, which you can then simply change the extension to .FDF and import them as notes into your PDF document.
Not being a powerpoint expert, I am not familiar with the intricacies of powerpoint notes. It appears, based on your screen capture, that they are positioned on the page somehow in. precise location. Hopefully, the notes are not just red boxes with red text.
Again, I'm not a scripter, so this idea of somewhat theoretical. An Acrobat scripter would be able to tell you for sure if this is possible.
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