Welcome in my coffee-nerd time ( feature image from Kirokaze ) The question is: how to create PDF dynamically and for free, without ANY commercial software ? With this kind of feature you may already know as the typical mail merge functionality in your preferred office application.
Scribus Generator provides this functionality, for free. It allows you to:
Generally speaking, Scribus Generator replaces text with data to automatically generate files (e.g. SLA, PDF). It has been originally written by Ekkehard Will and further extended by Berteh. A short how to video introduces this Scribus Generator. 6 first minutes for the basic overview, 12 last for some more advanced features.
More information here. https://github.com/berteh/ScribusGenerator