I had some interesting luck with the generic approach to unzip the DOCX/XLSX/ODT/etc, then to the contents recursively apply other filters like XML and JSON formatters/prettifiers.

(My work [1] in this space predated git so it wasn't written as a git diff filter, instead it automated source control. But the same principles could be used in the other direction.)

Not the highest level diffs you could possibly get, but at least for a programmer even ugly XML and JSON diffs were still nice to have over binary diffs.

[1] https://github.com/WorldMaker/musdex

I found this in my git starts: https://github.com/xltrail/git-xl?tab=readme-ov-file

And then there is also Pandoc that I guess could be helpful in this regard.