I know what you’re says but I think you need to use your public key as that is unique and will last forever. You can’t rely on 3rd party services like getalby.com to look after your identity as they could get compromised or disappear at any time.

I can’t remember what it called but I’m sure someone has proposed using a special type of private key that you would never use and just keep it safe. From that seed you would generate other keys that you would use day to day.

If you loose a key you could use the main seed to generate a new key and prove it was from the same seed, proving it is still you.

Sounds like a clever idea to solve the problem you mentioned because you’re right, people will loose or just compromise their private keys!