[nickzana]

That's essentially what passkeys are: a consumer-friendly name for on-device FIDO keys you can use over webauthn, along with (in the apple/google/Microsoft case) a mechanism for syncing/backup/recovery provided by your platform account provider. The keys are still backed by hardware, but instead of an external key it uses the internal platform security module (TPM, Secure Enclave, etc.)

You can use your phone without the syncing part to authenticate other device through a mix of a QR code, a tunnel server, and Bluetooth.