I agree with your comments about your experience. I recently also had an experience that ended on a third stage but I got an impression that they were very disorganized and they lacked proper interview skills/specialists/process to effectively conduct interviews including poor English language skills (not all though). I was surprised that at TikTok, all rounds of interviews are "elimination" based, so it's not like once you reach a certain level you can be sure you will have a loop panel interview with 4-5 stakeholders and one weaker/average interview wouldn't be a deal breaker as opposed to "rolling elimination-approach" one. I have had interviews with Linkedin, Google, FB, Twitter but I have never had such a great interviews like I did with TikTok + nice vibe/chemistry with the recruiters and rejection afterwards. Be careful and don't lose your focus if they are chit chatting with you - it doesn't mean you are doing well. A rejection was a huge shock to me, particularly that I didn't reach the last interview there and usually I am capable of reaching the last stage of the interview process at social media companies which more challenging/structurized process. There were 270 applicants to the role I applied - hence I stick to it as a reason behind my (too early) rejection.