It's not exactly simple as it involves some postgres specific knowledge, but you can make it reliable when working with transaction ids (see https://event-driven.io/en/ordering_in_postgres_outbox/).

I've had pretty much the exact same problem and what I went for in my low-volume case was to simply add advisory locks such that I can guarantee the transaction start times provide correct ordering.

Set the trigger to add the primary key + change time to a separate table, then scan/truncate that table to poll changes.