I don’t use TikTok, but a lot of the concern is just overblown China bad stuff (CCP does suck, but that doesn’t mean you have to be reactionary about everything Chinese).
There is no direct evidence that the CCP has some back door to grab user data, or that it’s directing suppression of content. It’s just not a real thing. The fear mongering has been about what the CCP could force ByteDance to do, given their power over Chinese firms. ByteDance itself has been trying to reassure everyone that that wouldn’t happen, including by storing US user data on US servers out of reach of the CCP (theoretically anyway).
You stopped hearing about this because that’s politics, new shinier things popped up to get people angry about. North Dakota or whatever tried banning TikTok and got slapped down on first amendment grounds. Politicians lost interest, and so did the media.
Now that’s not to say TikTok is great about privacy or anything. It’s just that they are the same amount of evil as every other social media company and tech company making money from ads.