You will see that I have posted about this before asking for suggestions on which software I can use to convert PDF to docx/odt.
I am a teacher. During my time as a researcher I wrote a lot of documents and regularly draw upon them to teach my students. I often have to take the text, modify them, or build upon them. A lot of my material is bound up in PDFs. Sometimes, I have grant applications to write where a previous draft I wrote was stored as a PDF. Converting them to text has become the bane of my life.
I am forced to use online tools because none of the software I have seem to do the trick. Lot of people keep saying pandoc. Pandoc does not convert PDF to any other format. It can only be the output format.
Is there a magic open source solution that I have missed out?
The only real solution is to always keep your source files. PDFs are not intended to be edited.