Datenna Full Stack Developer interview questions

Applied through LinkedIn, had an initial conversation with the recruter. Positive outcome. After that had a cultural / shallow technical talk with the CPO, positive outcome. And lastly a poorly structured system design interview with the CPO again. After that I got the generic rejection email. The entire process was really frustrating and unprofessional since I had to push recruiter for an answer and the rejection reason is not stated at all.