Monks Senior Backend Developer (.NET/C#) interview questions

This was probably one of the most difficult interview processes I've ever done. I applied online and before a single phone call I was issued a technical assessment. During this assessment I was given 2 hours to identify the functionality of a poorly written method, code review it, then write a relatively simple method to use Linq to sort data. They gave some unit tests to test the correct behavior of this method, however I found some of the unit tests to be broken. Not sure if that was part of the test. Once I passed that initial test, I got a simple culture/HR call. This asked your typical job interview questions. What salary do you want? What are your career goals? Why do you want to work here? etc... After that was a technical call. Here I got quized on my .NET/architecture knowledge. There were no gotcha questions. No CS trivia questions. Just stuff every good .NET dev should know. This should be a fairly easy interview for someone with experience. I passed that interview and was invited to a slack channel with a team of engineers where I was given a 16 hour assignment. They advised me that the suggested time was 8 hours. I was able to finish it in 10. Other interview reviewers seemed to suggest they were paid when they did this part. I was never offered payment. The project essentially was to take a very early prototype project, fix the unit tests, refactor it to a "minimalist architecture" then add some additional features on top of that. The features were all very normal requests for a microservice API. I did not pass this final assessment. It seemed like they had a very specific idea of how the design should look and mine didn't pass through that lens. They scheduled a call with me after the technical interview which I thought for sure was going to be an offer. But I was heartbroken to hear they were taking the very unusual step of rejecting me over the phone. The recruiter read me a list of feedback from the engineering team on why they rejected my project... but if I'm being honest I didn't really hear a word of it as I was processing the emotions from being rejected from a company I wanted to get hired by. My advice to people taking this final tech assessment is to use slack and clarify as much as possible. Make sure you are great with Clean Architecture and make sure you have a very clean separation between business logic and data layers (that seemed to be my downfall). Your architecture needs to be perfect and you need to have a perfect understanding of the inputs and outputs. Overall this process was a huge challenge and very time consuming. It was very disappointing to spend so much time and get a rejection. But I also felt the process was fair. No obscure trivia. No Leetcode or thought exercises. Just pure software engineering. They judged me by exactly the skills and knowledge I would need on the job.