I did some research about this a while back: https://utdemir.com/posts/choosing-cloud-regions.html#:~:tex...

You are right, the best region that optimises median latency against all internet users over the world is `us-west-3`, which is Paris - I believe. Likely because it has much better latency towards Asia where the majority of internet users are.

I also investigated which two regions to choose for a multi-region setup, which ends up being London and Japan.