Well, that’s where the problem lies. Or at least one of the problems. TikTok does detail what they collect, but the term “technical and behavioral information about your use of the Platform” is more than a little vague.
Steve pointed out an issue with fingerprinting in particular but, as far as most average users know, there’s no fingerprint scanner with TikTok. Actually, though, it appears there is. Because fingerprinting doesn’t just mean your actual fingers.