This topic is brought up again and again, even as far as 2017.
It is the highest on annoyance list as I use Affinity a lot for annotating heavily CADs, beyond what PDF handlers can provide, and creating figures and media based on PDFs. Often I get a PDF with embedded fonts from sources I can't control (datasheets, received CADs, etc.). The files are usually large drawings; rendering a flat pixel image is unthinkable (300dpi A2, yeah right haha). My workaround is to get a postscript version of the file by "printing" it through Postscript drivers (but then I also lose some editability).