Im not sure much can be done. Most of the people who dispute the science on climate change, or the evidence about Covid or the vaccines, that planes were hijacked on Sept 11 back in the day, refuse to hear anything that is said to them.
I think for some it is the only "power" they have in their lives, a way to fight authority.
others find a "community", while others refuse to listen to the science, as it would cause them to have to reflect on their way of life, or make sacrifices.
others just simply peddle the lies because their is money and fame in it for them.
i reckon all you can do is try to point to the facts, and if the conspiracy theorists continue to ignore them, walk away- at least from that topic.