Work experience - 2 years at a robotics startup with a flex role, did a lot of stuff as required
Recruiter contacted because I graduated from a reputed university

Online Assessment -

Got the exact same questions written here. Thanks to that comment, I was completely prepared. Finished the OA with 20 minutes remaining. Recruiter told me onsite will be on Feb 15.

On Site -

I was initially told that there will be an intro/behavioral round with no technical questions, then two technical interviews and then one system design interview. But, there was no introductory interview, was straight away put into technical. Recruiter had also told me that the interviews will be very generic and did not mention exactly which team I was interviewing for. Basically, a lot of confusion. All rounds were supposed to be 45 mins with 15 mins break, but the first two interviewers took the whole 1 hour slot.

First Interview -

15 minutes behavioral + https://leetcode.com/problems/course-schedule/solution/
I had not prepared for topological sort, so I did not know that was the optimal solution. I went for backtracking approach, which I could not finish in time, but I think the interviewer got the gist of my solution. Still, they weren't convinced.
Self assessment: No Hire
Lessons learned: Learn graph in depth

Second Interview -

5 mins intro + https://leetcode.com/problems/rotate-list/
I explained how I would solve it verbally in 5 minutes, then the interviewer changed the problem to rotate the linked list in the other direction instead. Again, I gave correct solution and time/space complexities. Then, I messed up the syntax in C++ <-- big red flag. It was even more unfortunate that the interviewer was super nice and was convinced that I would solve this quickly. Eventually, I was able to fix the syntax, but he suggested I should not use C++.
Self assessment: Most probably no hire
Lessons Learned: Learn Python for interview purposes

Third Interview -

5 mins intro + https://leetcode.com/problems/first-missing-positive/
I'm so glad I did not know this was a Hard problem because I would have freaked out. By far, my best round. I explained how I would do it brute force way, few other ways if time complexity was not constrained to O(n), if space complexity was not constrained to O(1), etc. Eventually we worked together on the optimial solution, interviewer seemed happy.
Self assessment: Hire
Lessons Learned: Keep your calm and ask clarifying questions to the interviewer

Fourth Interview -

Cannot stress how bad this interview went for me even though I had the solution. First of all, the connection was horrible. It was supposed to be a system design round, but the interviewer (who I also think was the hiring manager, this was never clarified because of lack of good connection) asked behavioral questions for 15 mins and then jumped straight into a coding exercise. The interviewer's tone was very condescending and he said "we work on large scale distributed systems here, not robots and toys". My friend later suggested that maybe he was playing "the bad cop" to see how I would react, but I honestly doubt it because of how unpleasant the whole interview was.

The question was to implement https://leetcode.com/problems/climbing-stairs/ as an API. I was a little taken aback because I was not expecting a low level system design interview, but luckily I knew how to solve it. I solved it using dp but he didn't seem happy with it, so I implemened using recursion, but he said he liked the dp implementation more. He also asked C# related questions which I did not know answers to (async, callbacks, etc). Then came the most fun part - he talked about the team, I finally knew what I was interviewing for.
Self Assessment: No hire
Lessons Learned: Keep your calm and don't get intimidated by scary interviewers

Conclusion

I don't think I will get the offer, and there's nothing to blame but my lack of preparation. I only started grinding leet code 2-3 weeks ago, and maybe I should not have jumped straight into interviews, but it's good to gain such experiences regardless. Overall, a decent interview experience apart from bad communication from recruiter and the last interview; but would definitely apply sometime again in future when I'm more confident with my skills (and this time, with Python).