Yes, on MacOS, the best way I found now since posting my first message is to open the pdf in Preview, go to the Print dialogue and save the file as PostScript xyz.ps file. It is then converted to curves, and opens up correctly in Publisher. A direct Save as… eps is not possible in Preview - and in all the other, non-Adobe Programs I found in said timeframe. pdfToolbox seems like a fine solution, but at 500€ it is a bit of an expensive solution for that problem. But thanks for the tip.
I have found some of those threads now, they are enlightening But it is remarkable as to not addressing this subject from Serif. I'm not a lawyer, but as loads of rather really small companies just implemented exactly that functionality, this strand of argument is quite frankly beyond me. And the technical feasibility should not be that high, for exactly the same reason. I don't need pdf editing - that's just not what pdf is for.
This has been an issue from day 1 beta of Publisher. A tough lesson to learn on a live project. The forums here are filled with the same issue though many people call it a feature as does Serif themselves I believe. The only options are to outline all fonts and then place in Publisher, or to convert to a high res JPG. Not ideal at all.
I think you got off pretty easy with yours. While it is different it is not horrible by any means and not a massive change from the intended look.
This is one HUGE reason I could not/ would not leave Indesign for Publisher.