It has been several years since I worked on a system that implemented listen/notify, but I recall there was a significant caveat that if the listener was unavailable at the exact moment the NOTIFY executes, the message would be lost.

That’s a significant risk for things that need to be in sync between two systems, so we stuck with listen/notify for info-level ops things and used polling/queue systems that offered better guarantees for more important tasks. Don’t want to be in a position where a quiet hiccup with a deploy or something results in fun bugs like 0.5% of rows being silently out of sync between ES and Postgres.