The Vax being harmful theory never made sense. They knew who would and wouldn't take it from the start. Everyone knew that conservative Christians weren't exactly going to line up for it. Wiping out your loyal useful idiots only to leave behind and have to fight well armed patriots isn't the DS plan.

If there is a devious plan, this is it. Throw out and hype COVID-19. Hype it enough to make it a pandemic. The useful idiots will self select themselves and get the shot. Everyone else will do the math and pass on the vaccine due to the low risk of the virus itself. Eventually they turn off C-19 and ramp down the vaccine production to nothing. Crisis over.

Give everyone plenty of time to pick their group before you release the real nasty virus, SARS-CoV-3 that goes with the vax. It's nasty and spreads faster than the wind. Miraculously the vax just happens to also protect against CoV-3. Give it a few weeks and all your true patriots are gone, leaving only useful idiot slaves behind.

Maybe there is a big DS plan worthy of a thriller novel, but I'm going with Hanlon's razor here. The DS managing to pull off such a coordinated plan like this is a bit of a stretch. A bunch of big pharma companies saw an easy way to make quick government money in some sort of heroic fashion to save the world. At the worst, they messed up and accidentally killed a chunk of the world, but they still got paid. Best case, they actually did save the world from C-19 and they still got paid.

Middle of the road case, they knew the risk was way overhyped. They put someone on it for a day or so to figure out how to just marginally reduce the risk of a virus with an already fractional risk factor. When it went from 0.0009 % down to 0.0001 %, they claimed 90 % efficacy and cashed their paycheck. Eh, they tested it on 30,000 initial test subjects and enough survived. Just enough to cash the paycheck of course.