Thanks for your very helpful suggestions!
I think the most reasonable step forward would be to migrate our
postgresql (our database probably won't outgrow a single server anytime soon, so it would be incredibly overkill to move to a distributed DB like Cassandra today. This might change in the future if our cluster sees massive and sustained growth, and if they all need to talk to the one DB, but that would be a good problem to have in a few years, and we'll definitely see it coming).
However, since our current
db.json already works reasonably well for our needs, I probably won't spend a lot of time migrating it to something more robust just now (unless the circumstances change and we suddenly need to migrate fast). Thanks again!