For anyone curious, the conspiracy theory seems to have some varieties, with the one I've most often seen pushed not so much claiming that 5G masts somehow directly cause coronavirus, but rather that coronavirus is a false-flag campaign designed to create broad popular support for a vaccine which, thanks to magnetic particles and/or nanotechnology depending on who's telling the lie right now, will enable mass population control via 5G masts.
I've been a hobbyist collector of conspiracy theories since high school. From that perspective, and absent any sort of context, I have to admit this one's inspired. But I gradually lost my pleasure in that hobby, as thoughtless social media operations turned conspiracy theories from a cute but harmless fringe preoccupation into a means of disinformation with the power to move whole societies. From that perspective, this is truly vile.
Do we have any reason to believe or disbelieve their methods?