Illustrator Action

My company customizes 20-page PDF proposals in Illustrator for hundreds of clients. We start by opening the individual PDF files, replacing certain words, then saving the files - last we combine the 20 PDF files into one document.

I’m looking for an action that that allows me to Open a PDF file in Illustrator, “Find and Replace” text, then Save the File. I could create the workflow to combine the PDFs into a single document.

Any ideas?