Amazon PM interview questions

Note: all interviews took place via telephone and Amazon Chime and NOT in person. The interview process stages were: 1. Phone interview with Amazon HR. 2. Phone interview with a Project Manager. 3. Numerical tests. 4. Provide a report of 1000 words about a decision that I made. 5. Interviews with 5 different Amazon employees back-to-back, including the hiring manager. One of them is called as the 'barrier'. That person is not the hiring manager. The 'barrier' is responsible to determine whether the candidate's skills will elevate the skillset of the overall organisation. Even though the hiring manager wants to hire the candidate, the 'barrier' has the power to reject the candidate. The overall interview process was thorough, and the questions were great and challenging. I was not expecting anything less for one of the strongest brands globally. Stage 5 occurred via Amazon Chime because the interviewers were based on different geographies. The first interview was with the Hiring Manager, who did not turn on his camera. The second interview was with the barrier, who turned on his camera. The rest of the interviewers did not used their cameras. After a few days, I was told that I did not receive an offer. Since I invested a lot of time and effort throughout the overall interview process, I asked for feedback for personal development but I did not hear anything back. From my perspective, I realised that I had not chances to get the job from the moment there was no camera in the first interview with the Hiring Manager. I have conducted interviews and hired people. Personally, I would never hire someone who I don't even know her/ his face. The rest interviews were just a waste of time. And I was right, as no one used its camera except of the barrier. Even though I asked them to turn on the camera, the interviewers did not accept it. It felt that they did not take my application seriously into account. From that moment, I cannot see how the barrier can take me seriously into account as well. The hiring process is great, challenging, and thorough. It demands a lot of preparation and strong performance to get the job. Considering that the interviews occurred via Amazon Chime and that there was not camera to 4 out of 5 interviews, it was challenging to demonstrate my full potential. What I would have done differently? I should have never accepted to do the most important stage virtually. I thought about emailing to HR about dropping my application straight after the first interview, but it would have been unprofessional from my side.