Dropbox Software Developer interview questions

I did OA and phone screen. During the phone screen, the HR did not ask too much questions about myself and mainly spent time talking about next steps. And then ghost me from there. This is not a good interview experience and a timely feedback or reject would be much better.

Initial coding exam with extreme difficulty, leetcode type exam with a time limit. After that you progress to an onsite interview with system design questions. The initial coding exam has about 3 multistep questions.