I don't understand the architecture section. The title is "layered architecture," but then it talks about Ports/Adapters, which would be hexagonal architecture?
I was about to leave a very witty "just be idempotent ;)" response but did not consider the nonce. I'd be surprised if Google is quick to change this, so I guess be stateful on the receiving server, persist that you handled a certain request already, and if you get a duplicate request, replay the response from the first one?
I really do not understand why this is a discussion, why a video had to be made about it and why we now need an interview about this.
Clean code / readable code / whatever you want to call it is often at odds with performance. This has been a known fact for decades. Everybody is aware of this. And for most enterprise projects it just doesn't matter.
The performance analysis discovered nothing new and added nothing of value