light is 186k miles per second, the other side of the globe is 12.5k miles away - so 67 ms / 130ms+ round trip in optimum conditions. Add more for network hops and consider that fiber is not quite as fast as vacuum.

300ms feels extremely optimistic coming from my perspective of someone living on an island in SE Asia

For a city that is far away from anywhere:

https://wondernetwork.com/pings/Auckland

Your real world latency is going to be worse.

This is a great example of information taking time:

https://www.ibiblio.org/harris/500milemail.html