3D FlipBook - Premium Customer - Speed Loading Issue

Reposting this as my last questions vanished. We have resized all our PDFs to the bare minimum possible, however, there is a 3-4 seconds delay from when we click on the link and open the page to when something appears on the actual page. We are basically seeing a BLANK page before the app loading appears.

This is far from optimal user experience as I can't expect at least 30% of users closing the page because they will think that the page is empty. Is there any way to fix this?

i postedd this in the wrong section. marketing as resolved and posting in WordPress