Ah this is a confusing part of our postgres interface.
The “right” way to add regional replicas is to create a new volume in the region you want, flyctl scale count 3, and then wait. Once flyctl status shows that it’s a healthy follower, you can flyctl volumes remove <old-volume> and then flyctl scale 2.
It seems like that db has been deleted, if you feel like giving it another try with a new one please let us know how it goes!