If it were me and needed what you're looking for "once" for a short period of time *and* you want quality output, I'd sign up for a US$25 one-month session for Acrobat DC and be done with it. Or, look up what's available from the manufacturer of the product you used to create the PDF files - that company may have a free-or-cheap conversion utility available.
Most of the apps on the MAS are crapware, and the Terminal scripts and Automator workflows utilize what's built into OS X - "solutions" I've found to be not satisfactory for my wants and needs. I used to use Distiller but now use Acrobat DC. That's my 2¢.