Great write-up—the distinction between healthy OS caching and actual memory pressure is often misunderstood. To get a granular view of where your memory is actually going (shared buffers, cache hits, etc.) without the overhead of heavy agents, pgmetrics (https://pgmetrics.io) is very effective. If you need to track these metrics over time to catch when 'good' caching turns into 'bad' pressure, pgDash (https://pgdash.io) builds directly on top of it to provide a specialized monitoring dashboard with zero-config setup.