Apart from biometrics all of these are things you would more or less expect them to collect. Words mentioned in the video and the videos popularity are important for the recommendation algorithm, and the censorship of "age inappropriate content". Location data similarly goes into the recommendation algo. Any social app asks for contacts nowadays (as much as I despise it).

The insidious thing is how the data is used. For example knowing the exact content of each video allows them to filter certain topics and promote others. Knowing your location allows them to use this geopolitically (showing content about the Ukraine war in some places, but not in others).

Whether intentional or unintentional, their recommendation engine infers demographic information. I'm pretty sure TikTok thought for a while that I was gay; videos with reasonably accurate predictions like "if this is recommended to you, you are a male between 25 and 30 who is introverted. You like to start projects but never finish them" were a trend for a while.

All of this gives TikTok and by extension China a great tool to influence opinions and moods in a finely targeted way. Take all the scandals about what Facebook experimented with, and how targeted ads influenced elections and votes, and give that power to one party with no oversight. That's TikTok.