I wanted to add django but their issues aren't on github as they are using their own system. IMO an external issue tracker lead to a higher barrier to create new issues, so this isn't not necessary fair.

Also fastapi allows people to ask questions with the issues. On the 1000+ open issues, 826 are tagged as question.

It's hard to find a fair metric. Open/close ratio rewards older project with fluctuating/stable popularity. Fastapi popularity is still growing[0], so having some difficulties to work on issues is expected.

[0] -- https://trends.google.com/trends/explore?date=today%205-y&q=...