Yes, this sounds like a nightmare and you should have used a reference manager :)

I can't speak on how to import anything to Zotero but you could use one of the AI tools (Copilot, Claude, ChatGPT) to look at the document a chapter at a time, and extract all the footnotes. So, upload the document (or a chapter if that's too big), then your prompt could look something like this:

In this document, footnotes look like these examples:
(put 2 or 3 examples in the prompt)
extract all the footnotes to a list of bibtex records
you could prompt the AI to add FIXME to record fields that it can't determine

Then you would have a list of references you can add to Zotero, and then re-cite in your document.

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Alternatively, if all you want to do is standardise the footnote format, you could ask the AI to produce some VBA that you can run over the document, a chapter at a time, to find the footnotes, convert them to text, then apply a standard footnote style.

The prompt (and this is just off the top of my head):
Write a VBA function to re-format footnotes to use the Footnote style. Existing footnotes look like these examples
(put 2 or 3 examples in the prompt)


This will still be a big task no matter how you do it, but if you can break it down into smaller tasks, you will find the AI can at least take care of some of the repetitive work.

You could try this dedicated tool

https://anystyle.io/

`Parses academic references in no time! Copy & paste your bibliography to get started…`

(see also [Structured references from PDF articles: assessing the tools for
bibliographic reference extraction and parsing](https://arxiv.org/pdf/2205.14677))