Ask HN: What's the largest serverless setup you've seen?

I'm looking for a serverless analogue to the Stack Overflow Architecture post from 2016: https://nickcraver.com/blog/2016/02/17/stack-overflow-the-architecture-2016-edition/

They're doing about 2500 requests per second. That just seems like an incredibly complicated setup (granted -- lots of redundancy, but still).

What I'm looking for are real war stories of scaling serverless up to 2500 - 5000 requests per second.

A few searches online only gives me theoretical tests, benchmarks and demos, but no actual apps in production. I'm looking for someone who actually does 2.5k+ requests per second on a serverless setup in production for a real app.