[1] https://neon.tech / https://github.com/neondatabase/neon
[2] https://access.crunchydata.com/documentation/postgres-operat... / https://github.com/CrunchyData/postgres-operator
[3] https://www.citusdata.com / https://github.com/citusdata/citus
Crunchy Postgres for Kubernetes is great if you're running Postgres inside Kubernetes, but is more of standard Postgres than something serverless. Citus also not really serverless at all, Citus is more focused on performance scaling where things are very co-located and you're outgrowing the bounds of a single node.
It's not clear to me that kiwicopple's work horizontally scales compute, ever. It seems it has to be just one server, and if you ran multiple they'd corrupt the S3 storage.
Neon: >= 3 nodes
kiwicopple/serverless-postgres: 0..1 nodes