I believe this plugin has a bug in it that prevents it from working properly on iOS. I use it a good bit on windows, and I have a vault mirrored to iOS via iCloud Drive and all my embedded PDFs break with the Better PDF plugin enabled. Worst part is that it also breaks normally embedded PDFs, which just show as a blank page. I recall reading a post some time ago by the plugin author – though I can’t find it now and my be mis-remembering – saying the he doesn’t use iOS and getting the issue worked out there is low on his list.