If what you said is the primary reason for banning TikTok (bad actors can do bad things), it's also a valid reason to ban literally every social network, or possibly even all user-generated content on the internet.
To the second, you misunderstand the issue the US government has here. It is not that the social network is compromised and can be manipulated to any number of uses by an external authority. It is that it is compromised and can be manipulated to any number of uses by an external authority that they are enemies with.
Whether you consider them your enemy, whether they consider you theirs, whether you think that China really is or is not an enemy of the US government, and whether you consider the US government your enemy or not is all irrelevant to the point at hand, as interesting as they may be in other contexts; this is about the beliefs of the US government.
China has similar concerns and has already taken numerous similar steps, and it's equally not any sort of hypocrisy or anything because the principle they operate under is not about the existence of control, but who has the control.
They can still kind of do it, but it requires a lot of work to fool other companies algo's into artificially promoting what you want. Much easier to just call up Bytedance and say "We need everyone in this area seeing this tiktok tomorrow".
Maybe consider that it's being banned because it makes it harder to control the political narrative and discourse in society when people have access to information. I think Chomsky put it best: there are many ways of population control, in the old Soviet Union it used to be the boot. In "democracy" it's controlling information and the Overton Window and TikTok breaks that completely. A great example is the Israel's assault on Palestine. Has this been covered anywhere where you watch news in even remotely the most honest way? Don't think so. Is it on TikTok? I think you know the answer.
I'd also say to single out TikTok and the Chinese while ignoring Meta and Google (why not ban them?) is very questionable if you really care about the scenario you described.
The US occupies a new office downtown. China wants eyes on a specific room, and the choice spot for monitoring it is someone else's apartment. This person happens to own a bakery also in town, and it sort of seems like the apartment is a reach for them as it is.
Now in your feed you get a short showing some egregious findings in the food from this bakery. More like this crop up from the mystical algorithmic abyss. You won't go there anymore. Their reviews tank and business falls. Mind you those posts were organic, tiktok just stifled good reviews and put the bad ones on blast.
6 months later the apartment is on the market, and not a single person in town "has ever seen CCP propaganda on tiktok".
This is the overwhelmingly main reason why Tiktok is getting banned.