As an OpenSearch and Postgres user
I want to easily keep these databases in sync
so that I can provide low latency, high throughput full text search that doesn't impact my transactional database.

Ever since search engines were invented, developers have struggled with keeping their system of records (typically relational databases like Oracle, Postgres, MySQL, etc) in sync with the search engine. Batch oriented processes are often not real-time enough resulting in poor user experiences where the search results don't return the same information as what's represented in the system of record. Event-oriented solutions such as writing updates from the app layer to Kafka which are then consumed by multiple databases can result in consistency issues and data stores becoming wildly out of sync, requiring a full re-index.

PGSync could be a helpful tool to address this common challenge: https://pgsync.com/