AIUI the concern is that you will only be able to use Passkeys that are held on devices that have been blessed. You will never get your custom solution blessed,

AIUI the concern is that you will only be able to use Passkeys that are held on devices that have been blessed. You will never get your custom solution blessed, so your access to your bank and government services will become dependent on being in good standing with Google. If your Google account gets deleted or your phone gets remotely deprovisioned, you will be unable to authenticate, and any attempt to create a "backup" against this situation that is fully under your control will be blocked by the attestation requirements.