I have also tried using "export=download" in the URL.
Does anyone know something obvious I am missing because it is strange even googling this is not really turning up results I am finding apply to my situation. I'm thinking CORS might be part of it. I have briefly examined setting it up and it seems rather involved and I feel like trying to do so maybe going down a rabbit hole that isn't actually going to solve my issue.
Yeah it is probably a CORS issue. As a workaround you can create a REST resource to fetch the PDF data, and then reference the base64 data from the REST resource response. Our PDF component supports base64 data. As long as the PDF isn't too large this should be fast enough for your use case. (If you have perf issues, then yeah you're going to need to figure out how to work with CORS.)
Thanks @bca I have used the base64 method before. I think I will maybe dig into the CORS issue or more probably, display an image preview(will already have a thumbnail of first page of PDF) and open pdf in browser with an on-click event. Thanks for confirming the CORS thing. I may now stop aimlessly drifting from similar help doc to similar list of google search results all night.