I spent many hours arguing with a smart friend about this. I was unable to find any argument to get her to stop believing 5G is boiling/damaging/altering people's blood with "high powered energy waves" or similar (the blood clot revelations have only amplified that conspiracy angle).
I find a commonality among most conspiracy theory people is vast ignorance of the topic in question and any underlying science. This isn't always true, however I've found it to be frequently true. They watch YouTube or Facebook videos on a conspiracy, someone states an incorrect thing that is held up as being scientifically correct; the conspiracy minded person has no idea it's wrong because of their ignorance of science, and their eagerness to consume conspiracies prevents them from being willing to do proper research. They buy in with no skepticism.
Often the conversation would end on a variation of: when the pandemic is gone, and 5G is still here, then what happens to your conspiracy? They had no reply, the future risk of being wrong didn't matter, only the mental juice of the conspiracy here and now. Or: what about locations where there is no 5G and people are still widely getting the virus? No answer. Or: why is this event so interesting as to warrant outlandish conspiracy theories, versus the pandemics of 1957 or 1968 or 1918, which were not caused by 5G? Or: why didn't 4G kill everyone, despite the absurd conspiracy theories about that as well? It usually does no good, they ignore the premise because that's in the past, they're all about the conspiracy now (it's the only place they can mentally hide, because the conspiracy going on now is usually still open-ended, yet to be crushed fully).
The conspiracy they're latched on to in the present is interesting because all big events are interesting to the conspiracy brain. Particularly big active events. Once an event is disproven, they usually instantly forget it ever existed or that they were ever wrong, and move on to the latest thing occupying the news or culture that is worthy of conspiracy theories (it typically has to be a major event or their brains won't latch onto it).
I'm convinced at this point in my life, after decades of arguing with conspiracy-minded types, that it's a mis-wiring or imbalance in the brain that tilts people aggressively toward being prone to falling for conspiracy theories. They also seem to need the rush of it (which again makes me wonder about an imbalance in their brains). The way they behave intellectually is incredibly similar; when you get inside their way of thinking via long discussions, you start to see weirdly repeating patterns of thinking, traps, failures of logic, and so on. I find that people prone to it, can't seem to help themselves, they swallow conspiracy theories widely about numerous topics and rarely are capable of intellectual skepticism. It almost strikes me as an illness in how they seem hostage to it, and sort of reminds me of drug addicts I've known. Like arguing with a helpless zombie that can't alter their behavior under any circumstances, no matter what evidence they're presented with.