to anyone who has the same problem, your phone needs to be replaced, it is a hardware issue. /thread
finally got my iphone x today after more than a month of waiting after the phone got stuck in korea for 3 days for no reason, out of the box, boom, face id is not available. called apple support, they admit it is a hardware problem and replacement phone is on it's way. tbh I am kinda used to apple's quality control nowadays, battery was defect for my iphone 5, front facing camera was mis-aligned on my iphone 6, been using android after that, finally decided to come back to ios and give x a try, o boy was I right. what would you expect on an iphone x? of course there is going to be something wrong with it. haha. good job apple!