I read an article somewhere debunking the whole HAARP theory that some antenna array in Alaska can alter the weather. Apparently it would need to be the size of like 1000 football fields and consume multiple a terawatts of power to make any difference. Difference as in even creating it's own aurora, not making it rain etc. It's just radio waves but you tell someone about the ionosphere and how radio waves work, now they think they are Heinrich Hertz and Nicola Tesla reincarnated lol.
If weather could be altered, meteorologists would be all over these anomalies because the weather models are now wrong since somebody turned on some device or sprayed something in the air. I doubt there is a conspiracy with all the meteorologists out there, both amateur and professional to hide a some secret. Even if there was at some point, the cat would be out of the bag years ago.
This is along the lines of some people who think there is a cure for cancer out there but "they won't release it" for some reason. If someone develops some new amazing tech or medicine, then they will try to be the 1st to market and make as much profit as possible.
There would be billions upon billions to be made by any company that can change the weather. If there was a way to do it at scale, it would have been invented by now unless it involves some futuristic Star Trek technology which we don't have.