Thanks! Feel free to send feedback to joe@breezepdf.com if you get the chance to try it.

Regarding your concern, if a manipulation of the PDF doesn't meet the standard specification, it won't render properly in a PDF viewer as it is in the present day, let alone in 20 years. All PDF viewers/editors worth their salt adhere to the PDF spec. So as long as the PDF specification stays the same, anything that renders correctly now in a PDF viewer will render correctly in the future.

For something like compression, if the file reduces in size and the PDF renders the same (minus expected potential minor quality loss), then you have evidence right there that it worked successfully.

I built BreezePDF with PDF spec adhering libraries, so everything should be up to standards.

Let me know if that answers your question!