It depends on what you value. If you want a computer that can produce Ed25519 signatures with a minimum of software and hardware complexity and a maximum of ins

It depends on what you value. If you want a computer that can produce Ed25519 signatures with a minimum of software and hardware complexity and a maximum of inspectability then you probably can't do better than a TKey. Yubikey on the other hand have a lot more features than TKey, for now.