What about Multigres[0]? It builds on top of Postgres and adds HA (based on Flexible Paxos[1]), sharding, etc. They're still not production-ready, but I'm highly optimistic they will solve a lot of the problems Postgres have.
For example, with Multigres, you should be able to achieve true zero downtime major version upgrade by simply resharding [2]. With vanilla Postgres + pgBouncer, you can only achieve near-zero downtime (few seconds at most), though it's probably good enough for most use cases.
For example, with Multigres, you should be able to achieve true zero downtime major version upgrade by simply resharding [2]. With vanilla Postgres + pgBouncer, you can only achieve near-zero downtime (few seconds at most), though it's probably good enough for most use cases.
[0] https://multigres.com/
[1] https://fpaxos.github.io/
[2] https://multigres.com/docs#migrate-across-postgres-versions