Exactly my concern with this scheme from keychainX because I know that recovery of lost wallet is done with past phrases so I honestly was wondering how recovery can be done without seed phrase.
There is no way you can retrieved a wallet without the seed phrase unless it's a custodian wallet that is owned be an exchange.
It's only the exchange that have the private key of the wallet and what you are limited to is the password they allowed you to create so you can access the wallet. I don't think there is any way someone will tell me that he can retrieved a wallet through the public keep only. Maybe in the future, that can be done by Quantum computers.