Wish I had this to share with my boss years ago. My first big project at my first post-college job was building a PDF parser that would generate notifications if a process document had been updated and it was the first time the logged in user was seeing it (to ensure they read the changelog of the process). Even with a single source of the PDFs (one technical document writer) I could only get a 70% success rate because the text I needed to parse was all over the place, when I stated we would need to use OCR to get better results no further development was done (ROI reasons). The technical writer was unwilling to standardize more than they already had, or consider an alternative upload process where they confirm the revision information.. which didn't help.

I don't envy working on ingesting even more diverse PDFs.