Copper or silver-based should be lower resistance. These conductive paints tend not to be very conductive, the carbon stuff is essentially making a thin-film carbon composition resistor. Good for repairing rear window defroster heating elements, not so great as a 0-ohm trace in a keyboard. For short (<1cm) wires it’s usually not too bad, but with the amount of damage I’m not sure you’ll be able to repair the thing.
It looks like it might be from a Model M-style keyboard. Unicomp sells those.