I don’t know what you think a “regulation” is, or what you mean by “crafting new ones”. Your question doesn’t make much sense to me.

If you’re asking in good faith and wanting to learn, not just win an internet argument, let’s get into it. The pro-corporate anti-trust standard since the Reagan years is called the “Consumer Welfare standard”. According to that standard, to simplify, a merger is bad if it leads to market inefficiency or higher prices for consumers. It’s a hyper libertarian standard. It is notoriously hard to prove and has led to massive concentration of the market.

The New Brandeis School takes a broader look at the market harms, such as harms to the labor market or to market platform choice. That means, to simplify, that a greater range of corporate behavior is deemed unacceptable that we’re previously considered fine. When corporations are found violating the new standard, they are sued by the FTC, and the courts decide the penalty. So your question doesn’t make sense. Change in enforcement regimes is what a regulation is.