First round is purely technical round and they ask for different AWS services you know or your past experience of working on Solution Architect role and how you designed the overall solution , During the Loop interview they will judge your based on your past performance (I find that approach is useless as in past we could not not done great work but it does not mean in future we will perform based on our past) , they will formulate questions on their leadership principle but they will not give you any human touch or expression which could make you feel they are not interested in your skills