I'm honestly thinking that the only answer to AI misinformation slop is misinformation about everything. Republicans post misinformation slop like there is no tomorrow. Do the same thing back. It's quick, easy, cheap. Keep AI videos coming about how immigrants are saving puppies in the US or something.
It'll grind the internet to a point where almost everything is lies and bullshit and there will only be a very few places left where actual useful information can be found (hello Wikipedia!). This'll happen anyway but this will speed up the process.
With this, soon enough nobody will believe anything anymore. It's sad that we're there but that's the world we live in now.