OCR PDF unfortunately no, PDF without OCR yes.
If the NAS is a capable NAS, then it will probably work with a little effort.
That is, if it can host Docker containers.
I have a Synology DS218+.
I had started once, but unfortunately didn't quite finish due to lack of time....
Getting started: jbarlow83/ocrmypdf

Good luck and if you get it to work completely, then a how-to answer would be great :-)

Jogi

Save... 🧐