audited regularly

You won't overturn hundreds of thousands of years of human nature and ungodly profits this way. People already have the ability to vote with their wallets and they don't for the most part. We do have at least one example of someone who tries, but I wonder how much of that page is still true today: https://stallman.org/stallman-computing.html

I was surprised to find the old Edward Bernays books online. I guess they're just that old now. From the first book Propaganda:

In theory, everybody buys the best and cheapest commodities offered him on the market. In practice, if every one went around pricing, and chemically testing before purchasing, the dozens of soaps or fabrics or brands of bread which are for sale, economic life would become hopelessly jammed. To avoid such confusion, society consents to have its choice narrowed to ideas and objects brought to its attention through propaganda of all kinds. There is consequently a vast and continuous effort going on to capture our minds in the interest of some policy or commodity or idea.

• https://www.gutenberg.org/cache/epub/78634/pg78634-images.html
• https://www.gutenberg.org/cache/epub/61364/pg61364-images.html

Stallman's notions probably aren't going to manifest themselves in the middle of nowhere without internet. Bernays' probably will.

You could force every social media to get their code audited regularly

Halting Problem goes brrrrrrrrrrrr...

This is unenforceable. The absolute best case is requiring something trivial, like serving content by recency. And even that can be gamed, aside from defeating the base offering of social media (connecting you to people and topics that interest you)