I think what I really want is managed backups that live outside of my box, and the ability quickly restore from one if my database crashes or becomes unusable. I think automated failover to another node may not be a reasonable ask for such a cheap product.
Of course, at that point: I could spin up a 1GB DigitalOcean volume for $0.10/mo, and set up scripts to run `pg_dump` every couple hours, clean the volume of older backups to free up space, and ideally a script to reset the database to a given volume. _That's all stuff I don't want to do_, but maybe someone's built a reusable set of scripts for it or something - that Dokku container is promising as a starting point, though I'm a little annoyed it only works with S3(-compatible).