If you’re a regular internet user the Personal Data Storage paradigm won’t move your data from the cloud to your personal computer. Most people will still rely on an institutional cloud service, but instead of data-banking with a shareholder-controlled corporation people’s data can be entrusted to the equivalent of member-owned credit unions for data storage.
There’s a corp solution called “CyberArk” that’s intended for storing passwords and other secrets and providing an audit trail for every access, as well as access controls, etc. It’s nothing like a solution for personal data storage, but those core concepts would be great.
The trick is getting Meta, Alphabet, X, banks, retailers, libraries and the rest to agree to use this API for storage of your data. The next (impossible) trick is enforcing their secure deletion of copies of your data in a timely fashion after they have accessed it.