Weirdly, it opens fine (but slowly) in iOS Safari...
mupdf worked like a charm! Any idea what makes it so performant (or evince so little)?
mupdf is, in my experience, much faster than poppler for complex documents, but mupdf-based viewers generally offer less features than those employing poppler's services (like Okular). These two things might be related.
Okular will do it, just takes a minute to do so. There are a huge number of layers to the PDF so it's rendering a lot of detail.
I could only open it with Gimp (which rasters it to a bitmap) on Ubuntu with the installed default software.