That they knew the laptop was real is obvious - they were sitting on it for a year.
The question is: what can you prove in a court of law? Let's even assume that you have proved that they were knowingly lying, can you tell which law was broken? What was it? It wasn't violation of the 1A (nothing in the 1A about government agents lying). Maybe you could construct it as libel against the NYPost? But can someone be libeled anonymously? They didn't mention NYPost by name.
That's the the law at present. I doubt if you could even use anti-trust laws against the social media companies colluding to censor. Most of these laws concern extracting monopoly rents from customers, and in these case users are not customers, and certainly they haven't paid unfair prices.
The existing laws simply do not fit this new situation. This kind of mass censorship by monopolies wasn't technically possible before. There will be push from both sides to regulate social media, but this will open another can of worms, because it's hard to define what precisely are we trying to forbid here. Should social media companies be completely banned from removing legal content? What about thematic forums where you ban off-topic content? What about spam, porn and gore? Should it only be applied to monopolies/cartels? Imagine debating this in the boomer-infested Congress.
I predict that the left will push for some 'expert' board (like the Jankowicz one) in charge of what can be said, while the GOP will successfully challenge that on 1A grounds. But since they can't rely on private companies being on their side, they will probably try to somehow strip them from the section 230 protections if they moderate too much (this is being done already in the judiciary). This in turn will backfire and result in a wave of lawsuits from malicious actors whose spam and porn was removed by some random mod, possibly causing exodus. It's going to be a shitshow in the next couple of years.