e.g. Envoy (which replaced Ocelot in Microsoft's .net microservice reference architecture) has a significantly lower latency cost (1)
Your reference to an Amazon reward is interesting as it's quite easy to get pages to load under 10ms in the right conditions. Perhaps you can provide a link to more information?
1. https://docs.microsoft.com/en-us/dotnet/architecture/microse...
If you want to really focus on performance, you can choose not to use anything like that off the shelf and do it all in a fraction of a millisecond. It actually isn't difficult - you just need to not get stuck into a dependency on something heavy.
For my company's backend, our entire middleware stack incl auth checks is around the 1-2ms level including hitting a DB server to check for token revocation. That's all there is between the end user and our application code, plus network latency. We didn't do anything particularly clever or special. But we didn't use any frameworks or heavy magic products - just Go's net/http, the chi router and Lambda@Edge.
Gateways can add a lot of functionality. Even Graphql can be used as a gateway.
It's not all "dumb forwarding" and I would be very surprised that you find any sub ms benchmarks.
Amazon has a one million dollar award if you get the page to load under 10 ms. So that's what you are expecting by default on a saas in your previous comment.
It's still unrealistic.