Mutually assured destruction has kept us from nuclear armageddon thus far, so do the same thing for the economy. Threaten to make things really really nasty for companies/politicians unless they play nice.

Move away from shareholder value as the be-all-end-all of a company's existence.

Reducing the privacy of the big players to almost nothing on pain of financial repercussions that are actually worth a damn would go a long way. Boardroom talks about "exactly how shitty can we make UI to milk maximum revenue out of our users before they just drop X product" should not be a private discussion. After all, as the NSA says, if you have nothing to hide you have nothing to fear, right?

Put a greater emphasis on different parts of education. How computer technologies work, psychology and how marketing, advertising, and social media abuse it, economics and all the stupid Wall Street financial creations that lead to Great Depressions, politics and how people play those games. Increase the level of awareness and jadedness among the general population so bad actors have a harder time getting the benefit of the doubt.

Do away with forced arbitration entirely. Enforce actual standards of customer service. Prosecute dark patterns and heavy-handed SaaS terms and EULAs. Maximize right-to-repair and couple it with an extreme reduction in the protection time for IP on things like schematics and software. Treat negligence, noncompliance, and bad-faith compliance as equal crimes. Companies taken to court can contribute to the public good by generously covering the costs of both parties unless they can prove beyond a reasonable doubt that a lawsuit is frivolous. Financial repercussions should be proportionate to annual revenue and be actually punishing. Executives who sign off on decisions that are detrimental to the general public should actually face prison, as should shareholders that pressure those decisions.

If corporations want to be people, they have a set death date in which they "pass", with a very high death tax. Place a scale limit on corporations, rather than giants they automatically get split up at some not that large a market size, and that C-Suite "graduates" to the business publication circuit, 'winners' but out of the game.

I don't think you can avoid cronyism so long as you have capitalism, but you can at least keep the size of those businesses in check such that the ability to affect politics is limited for any single one (or even a few together).

Yes, have a market-based legal system (a set of laws that are established via continuous market evaluation) instead of a politics-based legal system (a set of laws established by decisions made via a political system).