[simonw]

I know I'm playing armchair architect here, but MongoDB, PostgreSQL AND Elasticsearch?

For an application like this I would expect just PostgreSQL with its built-in JSON datatype and surprisingly capable full-text search to be enough on its own. I'd love to know how you ended up deciding on all three.

[PurpleRamen]

From the look of it it seams postgresql is used by keycloak for usermanagment-stuff, not by the app itself. So maybe this can be changed or even removed for selfhosting?