I agree. What counts as a positive signal for "scope" really very much depends what you're hiring for.

When looking for a manager type, people under management are a decent proxy. When looking for the world's greatest postgres optimization expert, some version of queries-per-second is prob the metric you want.

Or realistically if I needed the world's greatest Postgres expert (and could afford them), I would go talk to experts in the field and ask "Who's the best postgres person you know?" and work from there. At that point your resume is but a formality.