Doesn’t necessarily even involve compensation - lots of people will do agitprop for free just out of petty nonsense or a personal vendetta against another poster.
I agree, and think that’s the case with the vast majority of the shills that we see here. There are maybe a few that are part of a campaign, and the others have donated, are on an email list, get talking points, updates, links and then use that here, while keeping up the invective. They may not be in on the strategy and the effect they are trying to cause, but they play their part.