Klarna Senior Java Developer interview questions

Started with recruiter interview that took less than 30 minutes, he sent a reasoning test along coding test of a two easy problems on kattis ( smoothie maker and rejected transaction based on credit limit) then behavioral interview, it was good and I got a positive impression at the end by being told we hope to see you soon. Then tech skills interview to complete two easy tasks of a semi-ready code sent 1 day before the interview then a system design interview to design a saas platform for selling tickets of events/concerts which was also good and I got very good impression. After the system design interview they didn't reach out for 5 days, I sent an email then the recruiter called me and told me that the feedback on every tech interview was very good but in the behavioral interview they didn't feel like I have a lot of senior experience :) which is total nonsense then offered me another position with salary less than what I requested by 15000 sek which I instantly turned down.