I tried out PgDog a while ago, but couldn't find a good way of handling the config except for having this users / pgdog toml file, which makes it a bit awkward to handle in kubernetes where we often do multi-tenancy in postgres - or rather having many databases on the same instance(s), and have them come and go at will.
Also had an issue with it because it cached authentication requests when doing passthrough it seems, I'd changed the roles password, but it kept using the old one, which was no bueno ;).
PgDog seems to make more sense when you really care about a few databases that need massive scale, rather than a simple proxy in front of postgres. I'll keep following the development though, it is much needed in this space, postgres can use all the investment it can get to get it past the single machine scale that it excels at currently.
We successfully did this with pgdog at $JOB using our own "controller" -- the same service that handles deploying new instances of our application (instancing an argoCD Application that fires Crossplane DB creation, making new Deployments of bricks, etc) will also, at the end of that process, scan the cluster for Database CRDs, use those to generate a new pgdog.toml + users.toml, update the Secrets in the cluster, enable maintenance mode on all pgdog pods, do a live config reload on each of them, then disable maintenance mode (this is to make the change atomic between all the pgdog instances). Downtime there is about 2-3 seconds and all it does is make new SQL requests from existing clients wait, it doesn't break the connection or anything.