Have you noticed how the 5G thing has suddenly vanished? People were 100% sure that was the issue when COVID first arrived. People were burning down masts in the UK because they thought China was installing them as mind control tools. Now, not so much :)
It always starts with a slight element of truth, blown way out of proportion. There are some microwave frequencies for example that can cause headaches and flu-like symptoms if focused and fired directly at you. There are government level weapons that were fabricated and used in places like Russia and Cuba that worked like that, including quite recently -->. See this
.. but what would be the point of a government letting in a hostile country to attack it's own citizens en-masse? Makes no sense. Unless, of course, the government is part of a "flesh eating, lizard cult of blood drinkers that are controlled by Lucifer". Then it makes sense.
If you start off thinking the government is trying to kill you then anything sounds plausible. They could do it much more effectively by other means, e.g. the water supply. Things like 5G or 'chemtrails' would affect everyone, including the 'elite' or whoever is supposed to be behind it. Meanwhile we have a government who are trying to destroy all sorts of things such as the NHS and employment rights in plain sight. Wouldn't surprise me if they seed the conspiracies as a distraction, but then that is a conspiracy theory in itself :)