I just tried to install the Postgres AMI on AWS. You can't connect to it, and the documentation is wrong.
I installed the most recent pg13 AMI in Ohio. I was able to SSH in to the instance just fine, and able to connect from localhost using psql. But I could not connect from the outside world, even though the docs say that the only thing you need do is open up a hole in the security group.
To get it to work, I had to add
host all all 0.0.0.0/0 md5
listen_addresses = '*'
Also, it appears that postgres files appear in three different places in the directory structure: /bitnami, /opt/bitnami, and /home/bitnami/stack (through a symlink). Very confusing. Everything should be in one place.
Another suggestion: the big advantage that RDS has over a Bitnami AMI is automated backups. If you could find a way to configure it so it backs up to S3 automatically it would be really valuable.