It's interesting that some construction software is able to generate PDFs that a

It's interesting that some construction software is able to generate PDFs that are unreadable even by Acrobat Reader under Windows. "Cannot extract the embedded font 'XXX'…" it says, and then fails to render most of the text on drawings.

But I've found this gem: https://github.com/pdftl/pdftl

It can extract embedded fonts from a PDF into a separate folder, where you can overwrite the fonts with the "correct" ones (e.g. built-in Calibri with a proper Calibri from a Windows ISO file), and then repack the PDF back.

Magic.