TikTok Tech Lead interview questions

Interviewed by an arrogant robot from beijing, called himself a manager, started the interview with question and with no introduction. That's fine, while introducing myself, he interrupted me halfway by saying he used to work in amazon, not sure why. Asked one coding question, while I was thinking, quickly changed to another question. Must be fun working for this guy

Long story short. I went thru 3 rounds of technical interviews. All 3 rounds included a technical coding challenge and the last round included team management questions as well. The whole process lasted about 1 month. However, after wasting 1 month and going thru 3 rounds of interviews, I just received a generic email that says that they will not proceed further with me. I did not get any feedback or details on what did they find wrong about my skills or anything that I am lacking at. I finished all coding challenges, with a working solution and gave clear answers regarding team management. If I got this email after the 1st round, I wouldn't have minded it, however, after 3 rounds of interviews, I expected at least a small feedback from the manager. They also mentioned that the majority of the people are Chinese people and that some of them don't speak English, but only Mandarin. Maybe that's the reason why I wasn't hired since I am not Chinese and I don't speak Mandarin. Truly an awful interview process and I am really disappointed by this company.