Technical phone screens - Need a serious fix

Hi All, I have recently given few technical phone screens and based on my personal experience I feel like they need some serious fixes. In one of the interview - Question asked was to code “product of array except self”. I explained the optimal solution with O(n) time complexity and O(n) space complexity and implemented the code covering all the edge cases. So, the next follow-up question was to implement it in a O(1) constant space and O(n) time complexity. So, I thought about it and explained the interviewer that we cannot achieve a constant space O(1) solution with O(n) time complexity because in any case you would require atleast 1 output array of O(n) space to achieve O(n) time complexity solution. Explained the clear reasoning on why we cannot achieve it and showed him that if we make the solution space efficient i.e., constant space O(1) , time complexity of the solution increases to quadratic time O(n2). For next 15-20 mins, he was still mentioning that we can get a O(1) constant space and O(n) linear time solution. So, I said I’ll rethink if there is any other way we can achieve it. I still didn’t see a possibility to achieve the ask. Finally, when there was 5 mins left in the interview, interviewer realized that actually I was in fact correct in saying that we cannot achieve a O(1) constant space and O(n) time complexity solution at the same time. Since the interview leaned towards only technical without any behavioural questions, I was fairly confident that I will move onto next round. But I got an email from HR coordinator saying that they are not interested to move forward with me. I was little surprised with this. I just started thinking about transparency in interview process. Same happened with an other company. There was only O(nlogn) solution for the ask but the interviewer kept on asking for O(n) solution. I was obsolutely sure that we cannot have O(n) solution for it. Basically in phone interviews there is no one other than interviewer & interviewee. So, there is no one to verify/ second that interviewer is really correct/ wrong with his question/ solution or the observations/ analysis on a candidate. In on-site interviews there will be couple of interviewers doing the interviews so it is difficult to be completely biased on a particular person’s decision/ analysis on a candidate and there is less chance of mistake. So, I think it is always better to have 2 separate interviewers from different teams one actively interviewing and the other interviewer shadowing/ taking the notes. This way probably companies can reduce the bias in making any decisions on phone screens. It also helps the companies to do proper vetting before loosing the potential/ right candidates at phone screen stage. I know some of the companies are already doing it but not all. Do you think technical phone screens need some fix?