Definitely interesting how performance between different cloud DB services is so untransparent, similar to object storage [1]. Well, it wouldn't matter much with CSP lockin.
In addition to factors you can't control, maybe Digital Ocean has different Postgres params? I know MySQL for RDS has a bunch of knobs you should tune [2].
Yeah, cloud providers do advertise DBaaS as 'simple' but there's a reason they don't advertise anything on parameter tuning or say that they replace DBAs [1]. You pay them so that they give you a self-managed database, but they definitely leave a lot of work on your plate.
