Keybase got it right before Zoom acquired them. They decoupled identities from your account data. Basically they allowed you to claim identities via a dozen or

Keybase got it right before Zoom acquired them. They decoupled identities from your account data. Basically they allowed you to claim identities via a dozen or so different things they supported (email, phone, twitter, github, domain names, public pgp keys, etc.), and then prove that you owned it by posting some token, sending a message,. Which would then associate the identity with the account. The more identities you claimed, the stronger the proof that you were you. Taking a new device into use was as simple as authorizing it from one of your existing devices. All the data would sync over and be encrypted with a device specific key locally. And you could disable that key from any of the other devices. Too bad that company more or less failed. They never really figured out a business and the zoom acquisition looked more like an acquihire than a long term commitment to the product. But it's a good design that is worth copying.