I can't imagine that working, even if that AI were more reliable than currently possible. Someone who already disbelieves credible reporting and objective sources is not going to be swayed by an AI telling them to disregard their fantastical conspiracy theories. Especially not in a near-future world where everyone is inundated with AI fakery.

That's even without considering the efforts that would be made to undermine any system that showed any effectiveness. A lot of misinformation, probably most of the stuff that gets traction, isn't random, it's serving a purpose and being pushed for that reason.