I’m asking for existing tools/systems that let me programmatically say: “here is my public key, BUT if each of these 5 other public keys all send a signed message saying that my public key has been compromised, then you should mark my public key as compromised, and use the new one they provide”. (This is not for a particular task, I’m just curious if any existing auth systems are capable of this)

I call the idea “guardian keys” because it could be friends’ public keys or or just more-securely-stored less-frequently-used keys that you control.

NOTE: I know this would not work for data encryption. Encrypted data is simply gone if a key is lost. But, for proving an identity, like a login, there could be a system like this but I don’t know of any