I think that the key takeaway about using SketchUp in all this is that the vectors it exports to PDF are twice as much as you think it might be: One vector of the black (penned) outline, another vector of the blue (filled) shape.
I no longer have a Pro license for SketchUp (only Pro lets you export to PDF vectors), but I have a DXF plugin that exports line segments in a similar manner. Thankfully (somewhat) it doesn’t include the fill coloration on the exports, but it still has separate line segments (rather than beziers) because that’s just the way SketchUp works.