When I started on this codebase, we needed to implement some custom exchange logic that maps very neatly to fanout exchanges and non-durable queues in RabbitMQ and weren't built out on our PostgreSQL layer yet. This was a bootstrapping problem. Like I mentioned in the comment, we'd like to switch to pub/sub pattern that lets us distribute our engine over multiple geographies. Listen/notify could be the answer once we migrate to PG 16, though there are some concerns around connection poolers like pg_bouncer having limited support for listen/notify. There's a Github discussion on this if you're curious:
https://github.com/hatchet-dev/hatchet/discussions/224.