Advising a customer who has paid 3000€ for a computer (which was working perfectly and wirelessly with the SAMSUNG C410W Printer for the past three years) to contact the Printer Manufacturer, to tell them to create new Drivers for it... is at least RUDE and IMPOLITE.
APPLE has to understand that a customer is still a nice person, and that new products should be perfectly compatible with other devices, like the old products.
Thank God... there was a stubborn APPLE support guy in TELEPHONE APPLE SUPPORT (GREECE) named Thanos who told me:
Sir, you have a very good printer, it is a challenge for me to fix your compatibility from Remote (from distance)... and so he did, after 2,5 hours of persistent telephone co-working on my computer.
When I finally asked him what was the problem, he said that he was not sure and that it was probably the fact that some MALWARE was set up during the Download of CATALINA.
However, he said that the initial APPLE response from EAU ROUGE (... Your Mac, Your Responsibility) was, at least inappropriate and rude to a customer, as it was obvious that the problem began after Downloading CATALINA.
So, thank you all for joining in the Discussion, thank you EAU ROUGE for your response, and thank you Thanos for solving the problem.
By the way, SAMSUNG had already in my computer the New Drivers for CATALINA... so it was useless for me to contact the Printer Manufacturer and ask them to release new Drivers.