Thus my plot is the following: I would cover display with transparent film, using the fibre-tip pen with permanent ink map to this film the relevant Compact SeedQR and then, after placing this film on the steel plate hammer it with a punch tool.
I am unsure how efficient that idea would be considering the method. My main fear is that somehow your copied QR code isn't recognized and you are left with a metal plate that is not useful to your needs. I would tell you to test it before copying it to the metal plate but that would make you to use an exterior device (which I believe you don't want to).