[starttoaster]

"which cost almost nothing for low traffic" you invented the retort "what about high traffic" within your own message. I don't even necessarily mean user traffic either. But if you constantly have to sync new records over (as could be the case in any kind of timeseries use-case) the internal traffic could rack up costs quickly.

"vastly superior to self hosting regarding observability" I'd suggest looking into the cnpg operator for Postgres on Kubernetes. The builtin metrics and official dashboard is vastly superior to what I get from Cloudwatch for my RDS clusters. And the backup mechanism using Barman for database snapshots and WAL backups is vastly superior to AWS DMS or AWS's disk snapshots which aren't portable to a system outside of AWS if you care about avoiding vendor lock-in.