Tiktok grabs your IMEI number, amongst numerous other things and sends them back to the mother ship.
Not saying that other platforms don't collect data, but Tiktok is known for being a whole other level spyware. If Apple was truly trying to protect consumers, there's no way it would allow it.
Maybe I misunderstand you but the quick search[0] I did on Google says Apple iOS API doesn't allow programmer to fetch IMEI number. Did TikTok find a way to circumvent this and get the IMEI?
[0] https://stackoverflow.com/questions/41278494/how-to-get-imei...
[1] https://stackoverflow.com/questions/19927160/finding-imei-nu...
There is no ability to get the IMEI on iOS.
Somehow grabbing your IMEI is "whole other level of spyware" than Facebook, who had an app that was analyzing all the traffic sent through your phone.