Requiring a trial to do anything about a lie on social media would mean that there would be no change. By the time the trial comes, the lie is old news and there is some new conspiracy taking grip.
That would be, essentially, meaningless. Not in any way, shape, or form preventative.
We should change our laws to allow for more restrictions on purposeful lies that damage society. We shouldn't allow ExxonMobil to spend decades researching carbon emissions while knowingly lying about the conclusions of that research to the public. They should face repercussions for that as well as the people who knowingly spread that misinformation. I think that would be more effective than what you seem to be proposing which appears to be either limitations on recommendation algorithms or ad supported content.
>Would you be looking at criminalising lies and the spreading of them, even without knowing its a lie?
I don't know what you mean by this. We don't know whether a potentially defamatory statement is a lie or not until there is a trial. This would be no different. We don't need a Federal Truth Commission or anything. American society already seems satisfied letting a jury decide what is or is not a lie today.