Hi… This first one I think was more or less covered in the extensive discussion in the original announcement thread: people who want the higher level of convenience (or “it just works”) that you’re implying tend not to use the static egress IPs. (Not yet, anyway.)
They’re currently mainly only for those who are comfortable setting up their own NAT or userland repeaters, etc.
(There is some hope of getting Fly.io-managed versions of those in the future, 
, though—presumably at some extra cost.)
Also, it’s probably worth checking whether the external database can be accessed via WireGuard, which is better across every dimension.
That does sound anomalous, but it would be easier to gauge if you could post timings of individual Phoenix Machine → DB network calls. (It’s hard to infer without knowing how many queries there are per page, and such.)
Also, have you tried doing a traceroute (mtr) to the external database? I don’t know how well that works in this context, since the static egress IPs are at least partly based on tunneling (last I heard), but it might at least tell you the sub-path that traverses the public Internet. Perhaps you’re taking a scenic lake-shore detour through Chicago, or something along those lines…