Bot farms are extremely common but at the same time very unsophisticated. LLM technology (like ChatGPT) is still nascent enough that bots aren't really using it yet. Most bot farms are dedicated to those shitty YouTube comments about making $500 a day working from home. The technology isn't there yet to make it pump up anything other than metrics - which is to say they're only used to signal boost rather than change opinions explicitly.

Astroturfing as you've noted is also extremely common though that's a metric that's harder to measure since they at least attempt to be slightly covert. It is pretty obvious when you look at the content and the compare it to the engagement. This stuff is still pretty manual and me being a software engineer have no idea how it actually works under the scenes. Bot farms I have a bit of expertise.

BUT these two tools are obviously used in tandem. A few "marketers"/"propagandists"/"influencers" make astroturfed posts and they hit the switch on the bot farms to signal boost them.