Hardware wallets are designed to generate keys and sign transactions while never connecting to the internet The good ones like coldcard are designed specifically to hold private keys securely. And if the hardware device uses qr codes or nfc you can do all this without ever being directly connected to a computer that is connected to the internet. General purpose computers have much larger attack surfaces and are not designed to hold secrets like private keys securly. If you use a general purpose computer to generate keys, even if you "delete" them from the computer and back them up offline it is not a cold wallet.