Consistently

As read above , every time there is system design round i am keep getting rejected , dont know what to do , lossing hope , low level high level both, last interview interviewer asked me to design system to update data in distributed system without central coordinator, failed the same. I have given close to 50 interviews till date yet still failing. I have solved 630+ leetcode ,montly i get cleared in dsa, system design i have solved close to 30+ regular problems bothe lld and hld , still same why i am not sure can someone help here?.