All I've seen since TikTok boomed in US is that public opinion has been shaped very negatively on China by the hawkish tone in Washington.
I see zero, little evidence that TikTok brought any particular sympathy to China.
Nor I've seen a single study that has demonstrated that TikTok is any more biased than other socials. In fact it was even less than some (such as Twitter).
People seem to forget US focuses a lot on Americentrism. That didn't really change much with Tiktok and its alforithm is giving users more of what it determines to be interesting. I wouldn't be surprised if less than half the american users knew Bytedance was a chinese company before all these ban talks got off the ground.