Warren suggested a Wealth Tax that would offer a way to do this. I suspect there would be many new tax avoidance schemes used by the wealthy to avoid a cap, like investing in bogus companies overseas.I would limit the total wealth any individual or business entity could amass. I don't care how quickly they get there, that is, how profitable they are, as long as not doing so illegally (despoiling the land), unethically (exploiting employees) or via oligopolies (price fixing and gouging). It is an existential risk to the rest of us.
This is just a principle. I don't have suggestions for what those caps should be, or specifically how to implement this.
I also agree with Windfall taxes, as many companies do take avantage of demand to make excessive profits. Commerse in the USA gets away with a lot of unethical actions. There seems to be a great deal of deference to banks and industry by the federal government.