Confluent Frontend Developer interview questions

One OA, first round technical, second round technical, and final behavioural interview. The second round technical and final behavioural are back to back. They are very quick to get back to you on if you've moved on or not.

Three technical stages (HackerRank 2 questions, frontend discussion and some live coding, live coding algorithmic challenge), followed by a final "cultural fit" stage. The cultural stage was not a cultural stage. After passing three technical stages I was rejected with a generic email. I had to chase up to ask for feedback and the reason was I was assumed to be not technically component enough during the cultural fit stage. The interviewer has a PhD and I am self thought, hence the assumption. It seems like a very unfair process since after passing three technical stages you are rejected based on an assumption during a "culture fit" interview. Then you get a generic email with no explanation. Speaks poorly of the company.