> do I understand that all database traffic gets routed to the leader? Do you serve read-only queries from the local replica?

No, and yes. The replica have a very large ping between them, serving everything from the leader would be extremely slow.

> The described setup looks like something that cockroachdb would be able to handle nicely, which perhaps is a little more battle-tested than what you wrote.

Thanks for the suggestion, I wasn't aware of Cockroachdb, I'll try to see how I can switch to that.

Also, "what I wrote" is just a small script to extend my previous setup (which used PostgreSQL) to replicae. I first read about Patroni, supposedly used by large companies, and went with that, before discovering that it requires a lot of monitoring, and can't work for a one-person team.