I don't see how this can be practical unless there's a "ministry of truth" with an API that can check all the text for correctness. Even then, the issue won't be solved as the same actors can simply mask their lies with misleading statistics or fake ads.
Want to scare off people of mass immigration? You don't have to lie that Turkey is about to join the EU, you can post ads about cheap plane tickets from Turkey for families of 8 that are available as soon as Turkey joins the EU. It doesn't even have to be a fake ad, you can set up an agency that will indeed sell those tickets(but you're fine because Turkey is not joining EU anytime soon).
Yes, maybe the mass social interaction capabilities empowered people who were previously a laughing stock but I don't think that the way to counter this is fact-checking on a publisher level. Even flat earthers gain some traction despite the abundance of facts available.