I've haven't used Cupcake yet tbh. My understanding is that it's a watch only wallet. Do you want a signing device or just cold storage? If you just want cold storage you could roll a key, load it into cupcake and just have it generate addresses you send to. But I don't think you can use it to sp...

The only better way I can think of to do this is: derive the seed (use coins or dice if you prefer) and record into steel, load it up into an isolated environment (phone or VM) and derive the #monero view and public spend keys, export those to the device you want to use and make the view-only wallet...