FWIW, that was the second time I interviewed at Google. The first time, which resulted in strong yes across the board at L7, the first system design was to design Youtube Video Upload. The second was a more practical problem about replacing a high-volume logging component where correctness was critical but environment was space-constrained (i.e. no ability to run old + new in parallel).

Those were my favorite system design rounds ever, thanks to the problems being interesting and the interviewers also being very dynamic. It was also pre-Covid, so it was just awesome whiteboard design sessions.

sigh I miss in-person interviews.