Issues with adding a printer in Plasma 6

I once added a couple of configuration lines from the Wiki on my laptop 1, in order to get printing ready.
At that time, I was still at Plasma 5.

I then added the printer to the system with the Printer KCM from KDE, and everything went fine.

Times goes by, I upgrade the laptop to Plasma 6, and I am still able to print with that device.

Now, I install Plasma 6 directly to a second laptop, and find it tricky to add the same printer, with the same settings and everything.

The UI of the KDE Control Module looks new, and the functionality seems to be removed.

The setting in question is:

  services.printing.enable = true;
  services.printing.drivers = [ pkgs.brlaser ];

  services.avahi = {
  enable = true;
  nssmdns4 = true;
  openFirewall = true;

Despite that being the very same driver, the system reports it is still missing the correct one: