> I'm sure there's a cryptographic way for my identity to be proven to any who I chose to prove it to
There is. The pattern is: generate a keypair locally, derive a DID (decentralized identifier) from the public key, and then selectively prove your identity to specific verifiers using digital signatures. No central authority ever holds your private key.
The key difference from the LinkedIn model: you never hand biometric data to a third party. Instead, you hold a cryptographic identity that you control. If someone needs to verify you, they check a signature — not a database. You can prove you're the same entity across interactions without revealing anything about who you are in the physical world.
This is exactly the approach behind things like W3C DIDs and Verifiable Credentials. The crypto has been solved for years; the adoption problem is that platforms like LinkedIn have no incentive to give users self-sovereign identity when the current model lets them be the middleman.
I've been building an open implementation of this for AI agents (where the identity problem is arguably even worse — there's no passport to scan): https://github.com/The-Nexus-Guard/aip. But the same cryptographic primitives apply to human identity too.