Passkeys for Google Accounts are now available

I believe that if the fido key is lost everything is lost. But I also saw that the file(s) on the fido key can be saved and if the fido key is lost it is possible after purchasing another one to reconfigure the new one.

If you lose the FIDO2 key then Google or other services like Microsoft lets you generate backup codes and then keep two paper copies one in your wallet and one in your home in a secure location. And perhaps even save a copy to a USB flash drive.