Applied on their website, then received an email and a call from the recruiter because she was familiar with someone I had worked with.

One phone round involved an algorithm question and a chat with an engineer.

Then, I had an on-site interview with four rounds, which included design, general coding (any language), algorithms, and behavioral questions.

I blanked on the behavioral questions, and I was shortsightedly vain in a couple of moments. So, I'm guessing (and hoping, for my ego) that it was a bad culture fit.

Self-reflect on past projects, strengths, and weaknesses.