Citadel Securities Software Engineer New Grad interview questions

I received an OA after applying online, it has two graph questions LC Medium/Hard, and the time limit is 60 minutes. I solved them within time and passed all test cases. Then I received an invite for a screening round and the round consisted of questions on your resume and a simple asset reallocation (Nothing fancy, very simple) algorithm. Later, I got invited for virtual onsite which consisted of three back-to-back rounds. In all these rounds there are questions on resumes, a few coding problems, and behaviourals. My coding questions were on bit operations, tree zig zag, hashmaps, and designing a search autocomplete efficiently. I answered all these questions within time, but still got a rejection.

I applied through referral and got contacted at the end of Jan, received OA, very easy questions. After two weeks, I got scheduled a phone interview, implemented an easy LC question and got scheduled for virtual onsite after two days. Had three interviews, all were meant to be 45 minutes but two of them lasted around 1 hour, and one lasted around 1.5 hours. implemented some data structure, and was asked questions about OS, IPC, Network Programming and Multithreading. Heard nothing after a week, then I sent a followup email to my recruiter, got a reply one day after saying "Our team is reviewing your feedback and will get back to you asap". And then i got a rejection email which is exactly the same as last year's. Sadaf