I use Patroni for that in a k8s environment (although it works anywhere). I get an off-the-shelf declarative deployment of an HA postgres cluster with automatic failover with a little boiler-plate YAML.

Patroni has been around for awhile. The database-as-a-service team where I work uses it under the hood. I used it to build database-as-a-service functionality on the infra platform team I was at prior to that.

It's basially push-button production PG.

There's at least one decent operator framework leveraging it, if that's your jam. I've been living and dying by self-hosting everything with k8s operators for about 6-7 years now.