Do any of the major platforms really have a handle on how to deal with these challenges? I'm not excusing the lack of oversight. But most companies that grow this quickly are a complete cluster inside. Imagine having to battle well funded state actors on top of trying to build a business.
Again, not saying Facebook shouldn't be held accountable. But it's always easy from the outside looking in.
I think your cause-effect is backwards. Moderation at scale does not work, and a social network does not have to be the all-out-for-clicks disinformation machine that Facebook is. The company chooses to make it that way because it is optimal for their bottom line; rage makes clicks, clicks make money. They already built the business, and they choose again and again not to change it. So, to your statement, it is not that the company accidentally grew to what it is today and now it is swamped with unsolvable problems; rather, the company solved a different problem and has no intention to solve the others (nor they can with this business model).
Twitter is kind of adequate - somewhat responsive, somewhat proactive, but primarily they have an API that's sufficiently open and accessible to anyone that social science researchers can identify and map the the networks and behavior of political actors.
Again, not saying Facebook shouldn't be held accountable. But it's always easy from the outside looking in.