Where did you get that “simple calculation” from? If Average user is worth to TikTok a dollar per day that means that ad buyers are willing to give it to TikTok from their advertising and marketing budget. Which means that the average user should spend at least few grands each year on advertised products and services, which does not seem likely.

Also, this is not how valuations are estimated. 180 billion _per year_ is a huge amount (for comparison Apple revenue for 2019 is 260B). One applies a revenue multiple that depends on the stage of the company and industry but for early booming social media site is in the range of 20-40. So the estimate of 105-110 probably comes from the range of 3-5 B yearly revenue estimate