Issues with pdf Portfolio

I created a pdf portfolio from outlook folders.  Previously I got an index and was able to search the portfolio.  My understanding is that this was done through Flash functionality.  I currently have Acrobat Reader DC and Acrobat Pro 2017, but when I open the file with either of those it only shows a single email and does not indicate there are other messages.  The file is 2GB so there should be more content than a single email.  The portfolio cover page says to open with Acrobat X or Acrobat Reader X but I do not believe these are options.  Any way to get the content from these portfolio files?  I saw a post from Arnold15d5 from 2/2/21 that seems to indicate that a) files in a portfolio can be seen and b) that acrobat DC is a fix.  That is not my current experience.

Thanks in advance.