Trezor Wallets Also Compromised with Implants
zetter-zeroday.com
zetter-zeroday.com
There is no single device that can sign transactions so an attacker would have to compromise your hardware key, phone and desktop at the same time. Then slowly drain it $1000 (or whatever your daily limit is) at a time hoping you don't notice and freeze the account. When it's frozen you can only unlock it with a recovery key that doesn't exist on any electronic device.
If you set it up right the only attack that's left is good old extortion.