If you want to take the issue of social media manipulation seriously, you need to take a moment to consider who is best positioned and best motivated to carry out these operations. The vast majority of the English-speaking social media platforms are headquartered in Silicon Valley, domiciled in the US. This includes TikTok. Despite all the hippie California Ideology bullshit, the Valley has been closely linked with the Pentagon since its inception (See Palo Alto by Malcom Harris, or Surveillance Valley by Yasha Levine as two examples of this history.) Today, these giant tech firms still live off the teat of military contracts. From Microsoft to Google to Amazon.
The social media platforms enjoy a regime of immense power and nil regulations. There are a lot of ways the state could cause these companies pain if it were interested, from rescinding contracts to imposing regulation, to engaging in some bona fide anti-trust litigation, but this doesn't happen because they have an understanding. These companies collaborate with the state in surveillance, they install figures like Jessica Ashooh at Reddit - straight out of the Atlantic Council - to run moderation policy. They facilitate counterinsurgency by sweeping up disclosures like the Blue Leaks and shutting down dissident communities in the midst of large scale civil unrest. They flood these platforms with war propaganda when it is convenient, lay the seeds of doubt whenever US interests are challenged abroad. They allow floods of fake users to post positively about US-aligned coups like the one in Bolivia, or the SOSCuba nonsense. We literally have military formations who's sole task is to manipulate opinion on social media.
These are the people manipulating public opinion on social media. They are the ones holding the keys to the platforms. The ones who DECIDE what the algorithm is going to show you day after day after day. The ones who let shitholes like r/The_Donald to run roughshod for years, then ban communities like r/ChapoTrapHouse in the middle of the biggest domestic protest movement in US history. The ones who remove moderators from places like r/PresidentialRaceMemes and replace them with ideologues from r/Neoliberal to ensure the website closes ranks against the most underwhelming candidate and political vision conceivable for the moment.
Seriously consider the power held by the people operating these platforms. What they believe. What their material interests are. Who they network with. Who they do business with. What constraints exist to severely punish them if they undermine the interests of state. Consider that, and balance that against the overblown panic about foreign influence bots. Which one do you think has a bigger impact?
States are massive, chaotic social systems. I'm not going to say that foreign influence ops don't occur, because within each state there are competing factions with different interests. But consider China is much more concerned with domestic conditions within their country than they are about what a bunch of Redditors, who they have blocked, think about them anyway. Consider the same about Russia. Consider the disparity in power these countries have to manipulate infrastructure owned and operated in the United States compared to the people who actually own it, and the state agencies which have the jurisdiction to destroy these firms if they step out of line.