While you're doing this, please also tell people to stop producing PDF files in the first place, so that eventually the number of new PDFs can drop to 0. There's no hope for the format ever since manager types decided that it is "a way to put paper in the computer" and not the publishing intermediate format it was actually supposed to be. A vague facsimile of digitization that should have never taken off the way it did.
PDFs serve their purpose well. Except for some niche open source Linux tools, they render the same way in every application you open them in, in practically every version of that application. Unlike document formats like docx/odf/tex/whatever files that reformat themselves depending on the mood of the computer on the day you open them. And unlike raw image files, you can actually comfortably zoom in and read the text.
You don't need the exact flowing of text to be consistent, outside of publishing. This is an anti-feature most of the time, something you specifically don't want.
Zooming is not something PDFs do well at all. I'm not sure in what universe you could call this a usability benefit. Just because it's made of vector graphics doesn't mean you've implemented zoom in a way that is actually usable. People with poor vision (who cannot otherwise use eyeglasses) don't use a magnifying glass, they use the large-print variant of a document. Telling them to use a magnifying glass would be saying "no, we did not accommodate for low eyesight at all, deal with it".