Interview process was really long, took over a month, had 5 rounds which included a 1 hour presentation. The final round which is typically 2-3 candidates max, had 6 candidates. Feedback was super vague.

submitting cv, introductory call, followed by an interview with the manager, and then a case study. The day before the first interview, the interview invite was postponed to the following day without the interviewer informing me, which was not the best since an email could have been nice. I was rejected after the introductory which only lasted 15-minutes and I got asked only three questions (tell me about your experience, salary expectations, and visa sponsorship for the UK). Working for their direct competitors, Rejection at this stage (e.g., only after a 15-minutes conversation) was unexpected I thought that my skills would align quite well with the job requirements. Hence, I politely replied to the rejection email asking for feedback, but I never got a reply from them....