In order to use MetaMask, even as just an interface and not an actual wallet, you must set it up with a seed. But this seed is stored on the PC and is the exact opposite of what you are trying to do with a hardware wallet. So, you set it up with a “dummy” seed that you never use (since it is not safe) and this allows you to connect your hardware wallet and MM so you can interact with sites using the MM interface…. Just do NOT use the “Account 1” it creates and do NOT click “create account” to get a nee address as it won’t be protected by the hardware device and the address will belong to the unsafe MM seed.