I'm going to be humble that I don't have a perfect "fix" that I'm confident would be a net positive. If anything, the most suspicious business practice being done anywhere in the US currently is the AWS cash cow subsidizing everything else Amazon does, to the ruin of dozens of other markets. I just don't know how I'd even word legislation that would rein that in, in a way that wouldn't be overly subjective (and thus subject to the whims of ultimately, the Supreme Court), not trivially bypassable by structuring ownership creatively, and also not having terrible overregulatory impacts. Like, should "Bob's Corner Store & Cigarettes" be able to sell milk for just $2 a gallon to try to bring people in to buy cigarettes, whose profits more than pay for that loss? Probably? And he should also be able to use the profits from his successful cigarette operation to run a money-losing arcade next door, if he wants.

But at what point does it become distorting the market? I deeply hate regulations which punish behavior "only for sufficiently succesful" players, and I've seen how the existing "special competition rules for monopolists" lead to endless debates of "but I'm not a monopoly!" and it seems really clear that all of the trillion-dollar-market-cap companies are too powerful (they own too many politicians) to ever let themselves be classified as such, no matter what.