GP is right that XMP-supporting FOSS software is heavily biased toward media-management software, especially for photos, and that there is a distinct lack of a good Free Software file manager that supports XMP generically: https://en.wikipedia.org/wiki/Extensible_Metadata_Platform#S...

I currently use a combination of my own filetype-detection-and-tagging software “CHECKING YOU OUT” (insert Dropbox meme here), Windows Explorer with “XMP IFilter Desktop Edition”, and voidtools' “Everything” 1.5:

https://www.ifiltershop.com/downloads/xmpfilter/readme.html#...

https://www.voidtools.com/forum/download/file.php?id=1376