My wife used to work with students to help them get through interviews, and one of her pieces of advice when interviewing is to ask near the end of the interview is if they have any concerns about them as a candidate. It gives the interviewer a chance to address the concerns and gives them a chance to get feedback to make future changes. I’m not sure how well this would work for a technical interview loop, since my wife was working with law students, and the interviews aren’t the same kind of technical, but it might sidestep/short circuit typical lack of feedback technical people complain about.