I’ve got a pair of YubiKeys that I use to back my passkeys. Works great; I’ve got passkeys that work within the Apple, Microsoft and Google ecosystems and don’t have to worry about password prompts for the most part — but I DO need a YubiKey handy to validate that it’s actually me at the device.
My keys use both NFC and USB-C and work across all my passkeys supported devices when I add in a USB adapter.
One spends most of its time in a safe deposit box, and the other lives on my physical keychain.
To use it, the person would need to be logged in on a device I own (that’s password protected) AND have one of the keys (which also requires a PIN).