The interview process is grueling and requires significant preparation. I would recommend recording yourself answering STAR-format questions so you can identify where your responses need improvement.
Overall, I understand why Amazon uses this format — hiring mistakes are expensive. That said, the process could probably be toned down a bit. At a certain point, it starts rewarding candidates who have paid for interview coaching and prep courses, which risks creating a more polished, overly scripted culture rather than identifying the best operators and thinkers.