If you're interviewing at Google, the expected answer to the interview question can't be to use Google's internal tools. "Use Postgres" is the standardized, understandable answer for anyone outside Google who needs to solve Postgres-shaped and Postgres-sized problems.

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.